Polypeptides and uses thereof for reducing cd95-mediated cell motility

ABSTRACT

The present invention relates to polypeptides and uses thereof for reducing CD95-meditated cell motility. In particular, the present invention relates to a polypeptide having an amino acid sequence having at least 70% of identity with the amino acid sequence ranging from the amino-acid residue at position 175 to the amino-acid residue at position 191 in SEQ ID NO:1.

FIELD OF THE PRESENT INVENTION

The present invention relates to polypeptides and uses thereof forreducing CD95-meditated cell motility.

BACKGROUND OF THE PRESENT INVENTION

CD95 ligand (CD95L, also known as FasL) belongs to the TNF (TumorNecrosis Factor) family and is the ligand for the “death receptor” CD95(Fas/APO1). CD95L is a transmembrane “cytokine” whose extracellulardomain can be cleaved by metalloproteases, to produce a soluble ligand.This soluble form was initially described as an inert ligand thatcompetes with its membrane-bound counterpart for binding to CD95, thusacting as an antagonist of the death signal. More recent findings haveshown that metalloprotease-cleaved-CD95L (cl-CD95L) can activelyparticipate in aggravating inflammation in chronic inflammatorydisorders, such as systemic lupus erythematosus (and may exertpro-oncogenic functions by promoting the survival of ovarian and livercancers and chemotherapy resistance of lung cancers). Binding oftransmembrane CD95L to CD95 leads to the recruitment of the adaptorprotein Fas-associated death domain protein (FADD) to the intracellularregion of CD95 called the death domain (DD). In turn, FADD binds tocaspases 8 and 10. This CD95/FADD/caspase complex is known as theDeath-Inducing Signaling Complex (DISC) and plays a pivotal role in theinitiation of the apoptotic signal. By contrast, cl-CD95L fails toinduce DISC formation and instead promotes the formation of an atypicalreceptosome that we have designated Motility-Inducing Signaling Complex(MISC) (Tauzin S, Chaigne-Delalande B, Selva E, Khadra N, Daburon S,Contin-Bordes C, et al. The naturally processed CD95L elicits ac-yes/calcium/PI3K-driven cell migration pathway. PLoS Biol. 2011;9:e1001090.). Accordingly, a compound able to reduce the reducingCD95-meditated cell motility is highly desirable.

SUMMARY OF THE PRESENT INVENTION

The present invention relates to polypeptides and uses thereof forreducing CD95-meditated cell motility.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The death receptor CD95 plays a pivotal role in immune surveillance.Binding of CD95L to CD95 leads to the formation of a molecular complexconsisting in the adaptor protein FADD and the proteases caspase-8 and-10. This complex is named death inducing signaling complex (DISC). Wefound that CD95 engagement activates the phospholipase Cγ1 (PLCγ1),which in turn evokes a calcium response through activation of Ins3PIns1,4,5 trisphosphate (IP3) receptor (IP3R) and then multimerization ofthe plasma membrane calcium channel Orail. Tumor cells exposed to CD95Lundergo a redistribution of Orail into the CD95 aggregate where ittriggers a localized calcium influx transiently inhibiting the DISCformation via the recruitment of Protein kinase C β2 (PKCβ2). Also, thiscalcium signal is able to promote cell motility. Overall, the inventors'data clearly indicate that inhibition of the CD95-mediated Ca²⁺ responseturns out to be an attractive process to simultaneously sensitize tumorcells to death and impair their motility. More recently, the inventorsfound that while PLCγ1 activation impairs DISC formation, FADD andcaspase-8 do not participate in the Ca²⁺ signal suggesting that theformation of a different molecular complex is required to evoke thecalcium response in cells exposed to CD95L. Pursuing this analysis, theyalso identified the intracellular domain of CD95 responsible for PLCγ1activation and its blockade by a TAT-conjugated peptide inhibits theCD95-mediated calcium signal. In summary, disrupting the CD95-mediatedCa²⁺ response by using this peptide represents a new therapeuticmechanism to reduce the CD95-mediated cell motility and thus offersmeans for the treatment of cancers but also auto-immune diseases.

Accordingly an object of the present invention relates to a polypeptidehaving an amino acid sequence having at least 70% of identity with theamino acid sequence ranging from the amino-acid residue at position 175to the amino-acid residue at position 191 in SEQ ID NO: 1.

As used herein, the polypeptide which ranges from the amino acid residueat position 175 to the amino acid residue at position 191 is named “DID175-191”.

As used herein, the term “CD95” has its general meaning in the art andrefers to CD95 to the receptor present on the surface of mammaliancells, which has been originally shown to have the capacity to induceapoptosis upon binding of the trimeric form of its cognate ligand, CD95L(Krammer, P. H. (2000). CD95's deadly mission in the immune system.Nature 407, 789-795). CD95 is also known as FasR or Apo-1. An exemplaryamino acid sequence of CD95 is shown as SEQ ID NO:1.

SEQ ID NO: 1: >sp|P25445|TNR6_HUMAN without signal peptide:RLSSKSVNAQVTDINSKGLELRKTVTTVETQNLEGLHHDGQFCHKPCPPGERKARDCTVNGDEPDCVPCQEGKEYTDKAHFSSKCRRCRLCDEGHGLEVEINCTRTQNTKCRCKPNFFCNSTVCEHCDPCTKCEHGIIKECTLTSNTKCKEEGSRSNLGWLCLLLLPIPLIVWV KRKEVQKTCRKHRKENQGSHESPTLNPETVAINLSDVDLSKYITTIAGVMTLSQVKGFVRKNGVNEAKIDEIKNDNVQDTAEQKVQLLRNWHQLHGKKEAYDTLIKDLKKANLCTLAEKIQTIILK DITSDSENSNFRNEIQSLV

According to the invention a first amino acid sequence having at least70% of identity with a second amino acid sequence means that the firstsequence has 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84;85; 86; 87; 88; 89; 90; 91; 92; 93; 94; 95; 96; 97; 98; or 99% ofidentity with the second amino acid sequence. Amino acid sequenceidentity is typically determined using a suitable sequence alignmentalgorithm and default parameters, such as BLAST P (Karlin and Altschul,1990).

In particular the polypeptide of the present invention is a functionalconservative variant of the polypeptide for which the amino acidsequence ranges from the amino acid residue at position 175 to the aminoacid residue at position 191. As used herein the term“function-conservative variant” are those in which a given amino acidresidue in a protein or enzyme has been changed without altering theoverall conformation and function of the polypeptide, including, but notlimited to, replacement of an amino acid with one having similarproperties (such as, for example, polarity, hydrogen bonding potential,acidic, basic, hydrophobic, aromatic, and the like). Accordingly, a“function-conservative variant” also includes a polypeptide which has atleast 70% amino acid identity and which has the same or substantiallysimilar properties or functions as the native or parent protein to whichit is compared (i.e. inhibition of the CD95-mediated cell motility).Functional properties of the polypeptide of the present invention couldtypically be assessed in any functional assay as described in theEXAMPLES 1&2.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 192 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 193 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 194 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 195 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 196 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 196 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 197 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 198 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 199 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 200 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 201 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 202 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 203 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 204 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 205 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 206 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 207 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 208 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 209 in SEQ ID NO:1.

In some embodiments, the polypeptide of the present invention has anamino acid sequence having at least 70% of identity with the amino acidsequence ranging from the amino-acid residue at position 175 to theamino-acid residue at position 210 in SEQ ID NO:1.

As used herein, the polypeptide which ranges from the amino acid residueat position 175 to the amino acid residue at position 210 is named“Calcium-inducing domain” or “CID”.

In some embodiments, the polypeptide of the present invention comprises18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35;36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53;54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70; 71;72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89;90; 91; 92; 93; 94; 95; 96; 97; 98; 99; or 100 amino acids. In someembodiments, the polypeptide of the present invention comprises lessthan 50 amino acids. In some embodiments, the polypeptide of the presentinvention comprises less than 30 amino acids. In some embodiments, thepolypeptide of the present invention comprises less than 25 amino acids.In some embodiments, the polypeptide of the present invention comprisesless than 20 amino acids.

In some embodiments, the polypeptide of the present invention isstapled. A “stapled” peptide is a peptide comprising a selected numberof standard or nonstandard amino acids, further comprising at least twomoieties capable of undergoing reaction to promote carbon-carbon bondformation, that has been contacted with a reagent to generate at leastone cross-linker between the at least two moieties, which modulates, forexample, peptide stability. More particularly “peptide stapling” is aterm coined for a synthetic methodology used to covalently join twoolefin-containing side chains present in a polypeptide chain using anolefin metathesis reaction (J. Org. Chem. (2001) 66(16); Blackwell etal., Angew. Chem. Int. Ed. (1998) 37:3281). Stapling of a peptide usinga hydrocarbon cross-linker created from an olefin metathesis reactionhas been shown to help maintain a peptide's native conformation,particularly under physiological conditions (U.S. Pat. Nos. 7,192,713;7,723,469; 7,786,072; U.S. Patent Application Publication Nos:2010-0184645; 2010-0168388; 2010-0081611; 2009-0176964; 2009-0149630;2006-0008848; PCT Application Publication Nos: WO 2010/011313; WO2008/121767; WO 2008/095063; WO 2008/061192; WO2005/044839; Schafmeisteret al., J. Am. Chem. Soc. (2000) 122:5891-5892; Walensky et al., Science(2004) 305: 1466-1470; each of which is incorporated herein by referencein their entirety). The stapled peptide strategy in which anall-hydrocarbon cross-link is generated by olefin metathesis is anefficient approach to increase the helical character of peptides totarget a-helical binding motifs. Unlike their unstapled analogues thesehydrocarbon-stapled peptides have shown to be a-helical,protease-resistant, and cell permeable.

In some embodiments, the polypeptide of the present invention is fusedto at least one heterologous polypeptide (i.e. a polypeptide which isnot derived to CD95) to create a fusion protein. The term “fusionprotein” refers to the polypeptide according to the invention that isfused directly or via a spacer to at least one heterologous polypeptide.In some embodiments, the fusion protein comprises the polypeptideaccording to the invention that is fused either directly or via a spacerat its C-terminal end to the N-terminal end of the heterologouspolypeptide, or at its N-terminal end to the C-terminal end of theheterologous polypeptide.

As used herein, the term “directly” means that the (first or last) aminoacid at the terminal end (N or C-terminal end) of the polypeptide isfused to the (first or last) amino acid at the terminal end (N orC-terminal end) of the heterologous polypeptide. In other words, in thisembodiment, the last amino acid of the C-terminal end of saidpolypeptide is directly linked by a covalent bond to the first aminoacid of the N-terminal end of said heterologous polypeptide, or thefirst amino acid of the N-terminal end of said polypeptide is directlylinked by a covalent bond to the last amino acid of the C-terminal endof said heterologous polypeptide.

As used herein, the term “spacer” refers to a sequence of at least oneamino acid that links the polypeptide of the present invention to theheterologous polypeptide. Such a spacer may be useful to prevent sterichindrances.

In some embodiments, the heterologous polypeptide is a cell-penetratingpeptide, a Transactivator of Transcription (TAT) cell penetratingsequence, a cell permeable peptide or a membranous penetrating sequence.The term “cell-penetrating peptides” are well known in the art andrefers to cell permeable sequence or membranous penetrating sequencesuch as penetratin, TAT mitochondrial penetrating sequence and compounds(Bechara and Sagan, 2013; Jones and Sayers, 2012; Khafagy el andMorishita, 2012; Malhi and Murthy, 2012). In a particular embodiment,the heterologous polypeptide is an internalization sequence derivedeither from the homeodomain of Drosophila Antennapedia/Penetratin (Antp)protein (amino acids 43-58; SEQ ID NO:2) or the Transactivator ofTranscription (TAT) cell penetrating sequences (SEQ ID NO:3).

SEQ ID NO: 2 for Drosophila Antennapedia/Penetratin (Antp) (amino acids 43-58): RQIKIWFQNRRMKWKKSEQ ID NO: 3 for Tat cell penetrating sequence Tat (47-57) YGRKKRRQRRR

The polypeptides or fusion proteins of the present invention may beproduced by any technique known per se in the art, such as, withoutlimitation, any chemical, biological, genetic or enzymatic technique,either alone or in combination. For instance, knowing the amino acidsequence of the desired sequence, one skilled in the art can readilyproduce said polypeptides or fusion proteins, by standard techniques forproduction of amino acid sequences. For instance, they can besynthesized using well-known solid phase method, typically using acommercially available peptide synthesis apparatus (such as that made byApplied Biosystems, Foster City, Calif.) and following themanufacturer's instructions. Alternatively, the polypeptides or fusionproteins of the present invention can be synthesized by recombinant DNAtechniques as is now well-known in the art. For example, these fragmentscan be obtained as DNA expression products after incorporation of DNAsequences encoding the desired (poly)peptide into expression vectors andintroduction of such vectors into suitable eukaryotic or prokaryotichosts that will express the desired polypeptide, from which they can belater isolated using well-known techniques. Polypeptides or fusionproteins of the present invention can be used in an isolated (e.g.,purified) form or contained in a vector, such as a membrane or lipidvesicle (e.g. a liposome).

In some embodiments, it is contemplated that polypeptides or fusionproteins according to the invention may be modified in order to improvetheir therapeutic efficacy. Such modification of therapeutic compoundsmay be used to decrease toxicity, increase circulatory time, or modifybiodistribution. For example, the toxicity of potentially importanttherapeutic compounds can be decreased significantly by combination witha variety of drug carrier vehicles that modify biodistribution. Forinstance, a strategy for improving drug viability is the utilization ofwater-soluble polymers. Various water-soluble polymers have been shownto modify biodistribution, improve the mode of cellular uptake, changethe permeability through physiological barriers; and modify the rate ofclearance from the body. To achieve either a targeting orsustained-release effect, water-soluble polymers have been synthesizedthat contain drug moieties as terminal groups, as part of the backbone,or as pendent groups on the polymer chain. For example, Pegylation is awell-established and validated approach for the modification of a rangeof polypeptides (Chapman, 2002). The benefits include among others: (a)markedly improved circulating half-lives in vivo due to either evasionof renal clearance as a result of the polymer increasing the apparentsize of the molecule to above the glomerular filtration limit, and/orthrough evasion of cellular clearance mechanisms; (b) reducedantigenicity and immunogenicity of the molecule to which PEG isattached; (c) improved pharmacokinetics; (d) enhanced proteolyticresistance of the conjugated protein (Cunningham-Rundles et. al., 1992);and (e) improved thermal and mechanical stability of the PEGylatedpolypeptide. Therefore, in some embodiments, the polypeptides of thepresent invention may be covalently linked with one or more polyethyleneglycol (PEG) group(s).

A further object of the present invention relates to a nucleic acidsequence encoding for a polypeptide or a fusion protein according to theinvention.

As used herein, a sequence “encoding” an expression product, such as aRNA, polypeptide, protein, or enzyme, is a nucleotide sequence that,when expressed, results in the production of that RNA, polypeptide,protein, or enzyme, i.e., the nucleotide sequence encodes an amino acidsequence for that polypeptide, protein or enzyme. A coding sequence fora protein may include a start codon (usually ATG) and a stop codon.

These nucleic acid sequences can be obtained by conventional methodswell known to those skilled in the art. Typically, said nucleic acid isa DNA or RNA molecule, which may be included in a suitable vector, suchas a plasmid, cosmid, episome, artificial chromosome, phage or viralvector.

So, a further object of the present invention relates to a vector and anexpression cassette in which a nucleic acid molecule encoding for apolypeptide or a fusion protein of the present invention is associatedwith suitable elements for controlling transcription (in particularpromoter, enhancer and, optionally, terminator) and, optionallytranslation, and also the recombinant vectors into which a nucleic acidmolecule in accordance with the invention is inserted. These recombinantvectors may, for example, be cloning vectors, or expression vectors.

As used herein, the terms “vector”, “cloning vector” and “expressionvector” mean the vehicle by which a DNA or RNA sequence (e.g. a foreigngene) can be introduced into a host cell, so as to transform the hostand promote expression (e.g. transcription and translation) of theintroduced sequence. Any expression vector for animal cell can be used.Examples of suitable vectors include pAGE107 (Miyaji et al., 1990),pAGE103 (Mizukami and Itoh, 1987), pHSG274 (Brady et al., 1984), pKCR(O'Hare et al., 1981), pSG1 beta d2-4 (Miyaji et al., 1990) and thelike. Other examples of plasmids include replicating plasmids comprisingan origin of replication, or integrative plasmids, such as for instancepUC, pcDNA, pBR, and the like. Other examples of viral vectors includeadenoviral, retroviral, herpes virus and AAV vectors. Such recombinantviruses may be produced by techniques known in the art, such as bytransfecting packaging cells or by transient transfection with helperplasmids or viruses. Typical examples of virus packaging cells includePA317 cells, PsiCRIP cells, GPenv+ cells, 293 cells, etc. Detailedprotocols for producing such replication-defective recombinant virusesmay be found for instance in WO 95/14785, WO 96/22378, U.S. Pat. No.5,882,877, U.S. Pat. No. 6,013,516, U.S. Pat. No. 4,861,719, U.S. Pat.No. 5,278,056 and WO 94/19478. Examples of promoters and enhancers usedin the expression vector for animal cell include early promoter andenhancer of SV40 (Mizukami and Itoh, 1987), LTR promoter and enhancer ofMoloney mouse leukemia virus (Kuwana et al., 1987), promoter (Mason etal., 1985) and enhancer (Gillies et al., 1983) of immunoglobulin H chainand the like.

A further aspect of the present invention relates to a host cellcomprising a nucleic acid molecule encoding for a polypeptide or afusion protein according to the invention or a vector according to theinvention. In particular, a subject of the present invention is aprokaryotic or eukaryotic host cell genetically transformed with atleast one nucleic acid molecule or vector according to the invention.

The term “transformation” means the introduction of a “foreign” (i.e.extrinsic or extracellular) gene, DNA or RNA sequence to a host cell, sothat the host cell will express the introduced gene or sequence toproduce a desired substance, typically a protein or enzyme coded by theintroduced gene or sequence. A host cell that receives and expressesintroduced DNA or RNA has been “transformed”.

In a particular embodiment, for expressing and producing polypeptides orfusion proteins of the present invention, prokaryotic cells, inparticular E. coli cells, will be chosen. Actually, according to theinvention, it is not mandatory to produce the polypeptide or the fusionprotein of the present invention in a eukaryotic context that willfavour post-translational modifications (e.g. glycosylation).Furthermore, prokaryotic cells have the advantages to produce protein inlarge amounts. If a eukaryotic context is needed, yeasts (e.g.saccharomyces strains) may be particularly suitable since they allowproduction of large amounts of proteins. Otherwise, typical eukaryoticcell lines such as CHO, BHK-21, COS-7, C127, PER.C6, YB2/0 or HEK293could be used, for their ability to process to the rightpost-translational modifications of the fusion protein of the presentinvention.

The construction of expression vectors in accordance with the invention,and the transformation of the host cells can be carried out usingconventional molecular biology techniques. The polypeptide or the fusionprotein of the present invention, can, for example, be obtained byculturing genetically transformed cells in accordance with the inventionand recovering the polypeptide or the fusion protein expressed by saidcell, from the culture. They may then, if necessary, be purified byconventional procedures, known in themselves to those skilled in theart, for example by fractional precipitation, in particular ammoniumsulfate precipitation, electrophoresis, gel filtration, affinitychromatography, etc. In particular, conventional methods for preparingand purifying recombinant proteins may be used for producing theproteins in accordance with the invention.

A further aspect of the present invention relates to a method forproducing a polypeptide or a fusion protein of the present inventioncomprising the step consisting of: (i) culturing a transformed host cellaccording to the invention under conditions suitable to allow expressionof said polypeptide or fusion protein; and (ii) recovering the expressedpolypeptide or fusion protein.

The polypeptides and fusion proteins of the present invention areparticularly suitable of reducing CD95-mediated cell motility and thusmay find various therapeutic applications.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for reducing CD95-mediated cancercell motility. In some embodiments, the polypeptides and fusion proteinsof the present invention are particularly suitable for the treatment ofcancer in a subject in need thereof. As used herein, the term “cancer”has its general meaning in the art and includes, but is not limited to,solid tumors and blood borne tumors. The term cancer includes diseasesof the skin, tissues, organs, bone, cartilage, blood and vessels. Theterm “cancer” further encompasses both primary and metastatic cancers.Examples of cancers that may be treated by methods and compositions ofthe present invention include, but are not limited to, cancer cells fromthe bladder, blood, bone, bone marrow, brain, breast, colon, esophagus,gastrointestine, gum, head, kidney, liver, lung, nasopharynx, neck,ovary, prostate, skin, stomach, testis, tongue, or uterus. In addition,the cancer may specifically be of the following histological type,though it is not limited to these: neoplasm, malignant; carcinoma;carcinoma, undifferentiated; giant and spindle cell carcinoma; smallcell carcinoma; papillary carcinoma; squamous cell carcinoma;lymphoepithelial carcinoma; basal cell carcinoma; pilomatrix carcinoma;transitional cell carcinoma; papillary transitional cell carcinoma;adenocarcinoma; gastrinoma, malignant; cholangiocarcinoma;hepatocellular carcinoma; combined hepatocellular carcinoma andcholangiocarcinoma; trabecular adenocarcinoma; adenoid cystic carcinoma;adenocarcinoma in adenomatous polyp; adenocarcinoma, familial polyposiscoli; solid carcinoma; carcinoid tumor, malignant; branchiolo-alveolaradenocarcinoma; papillary adenocarcinoma; chromophobe carcinoma;acidophil carcinoma; oxyphilic adenocarcinoma; basophil carcinoma; clearcell adenocarcinoma; granular cell carcinoma; follicular adenocarcinoma;papillary and follicular adenocarcinoma; nonencapsulating sclerosingcarcinoma; adrenal cortical carcinoma; endometroid carcinoma; skinappendage carcinoma; apocrine adenocarcinoma; sebaceous adenocarcinoma;ceruminous; adenocarcinoma; mucoepidermoid carcinoma;cystadenocarcinoma; papillary cystadenocarcinoma; papillary serouscystadenocarcinoma; mucinous cystadenocarcinoma; mucinousadenocarcinoma; signet ring cell carcinoma; infiltrating duct carcinoma;medullary carcinoma; lobular carcinoma; inflammatory carcinoma; paget'sdisease, mammary; acinar cell carcinoma; adenosquamous carcinoma;adenocarcinoma w/squamous metaplasia; thymoma, malignant; ovarianstromal tumor, malignant; thecoma, malignant; granulosa cell tumor,malignant; and roblastoma, malignant; Sertoli cell carcinoma; leydigcell tumor, malignant; lipid cell tumor, malignant; paraganglioma,malignant; extra-mammary paraganglioma, malignant; pheochromocytoma;glomangiosarcoma; malignant melanoma; amelanotic melanoma; superficialspreading melanoma; malig melanoma in giant pigmented nevus; epithelioidcell melanoma; blue nevus, malignant; sarcoma; fibrosarcoma; fibroushistiocytoma, malignant; myxo sarcoma; liposarcoma; leiomyo sarcoma;rhabdomyo sarcoma; embryonal rhabdomyosarcoma; alveolarrhabdomyosarcoma; stromal sarcoma; mixed tumor, malignant; mullerianmixed tumor; nephroblastoma; hepatoblastoma; carcinosarcoma;mesenchymoma, malignant; brenner tumor, malignant; phyllodes tumor,malignant; synovial sarcoma; mesothelioma, malignant; dysgerminoma;embryonal carcinoma; teratoma, malignant; struma ovarii, malignant;choriocarcinoma; mesonephroma, malignant; hemangio sarcoma;hemangioendothelioma, malignant; kaposi's sarcoma; hemangiopericytoma,malignant; lymphangiosarcoma; osteosarcoma; juxtacortical osteosarcoma;chondrosarcoma; chondroblastoma, malignant; mesenchymal chondrosarcoma;giant cell tumor of bone; ewing's sarcoma; odontogenic tumor, malignant;ameloblastic odontosarcoma; ameloblastoma, malignant; ameloblasticfibrosarcoma; pinealoma, malignant; chordoma; glioma, malignant;ependymoma; astrocytoma; protoplasmic astrocytoma; fibrillaryastrocytoma; astroblastoma; glioblastoma; oligodendroglioma;oligodendroblastoma; primitive neuroectodermal; cerebellar sarcoma;ganglioneuroblastoma; neuroblastoma; retinoblastoma; olfactoryneurogenic tumor; meningioma, malignant; neurofibrosarcoma;neurilemmoma, malignant; granular cell tumor, malignant; malignantlymphoma; Hodgkin's disease; Hodgkin's lymphoma; paragranuloma;malignant lymphoma, small lymphocytic; malignant lymphoma, large cell,diffuse; malignant lymphoma, follicular; mycosis fungoides; otherspecified non-Hodgkin's lymphomas; malignant histiocytosis; multiplemyeloma; mast cell sarcoma; immunoproliferative small intestinaldisease; leukemia; lymphoid leukemia; plasma cell leukemia;erythroleukemia; lymphosarcoma cell leukemia; myeloid leukemia;basophilic leukemia; eosinophilic leukemia; monocytic leukemia; mastcell leukemia; megakaryoblastic leukemia; myeloid sarcoma; and hairycell leukemia.

In some embodiments, the polypeptide or fusion protein of the present isparticularly suitable for the treatment of triple negative breastcancer. As used herein the expression “Triple negative breast cancer”has its general meaning in the art and means that said breast cancerlacks receptors for the hormones estrogen (ER-negative) and progesterone(PR-negative), and for the protein HER2.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for the prevention of metastases(e.g. in a subject suffering from a triple negative breast cancer).

In some embodiments, the present invention relates to the polypeptide orthe fusion protein of the present invention for use in enhancingtherapeutic efficacy of cancer treatment in a subject in need thereof.In some embodiments, the polypeptide or the fusion protein of thepresent invention may be administered sequentially or concomitantly withone or more therapeutic active agent such as chemotherapeutic orradiotherapeutic agents. Examples of chemotherapeutics include but arenot limited to fludarabine, gemcitabine, capecitabine, methotrexate,mercaptopurine, thioguanine, hydroxyurea, cytarabine, cyclophosphamide,ifosfamide, nitrosoureas, platinum complexes such as cisplatin,carboplatin and oxaliplatin, mitomycin, dacarbazine, procarbazine,epipodophyllotoxins such as etoposide and teniposide, camptothecins suchas irinotecan and topotecan, bleomycin, doxorubicin, idarubicin,daunorubicin, dactinomycin, plicamycin, mitoxantrone, L-asparaginase,doxorubicin, epirubicin, 5-fluorouracil and 5-fluorouracil combined withleucovorin, taxanes such as docetaxel and paclitaxel, levamisole,estramustine, nitrogen mustards, nitrosoureas such as carmustine andlomustine, vinca alkaloids such as vinblastine, vincristine, vindesineand vinorelbine, imatinib mesylate, hexamethylmelamine, kinaseinhibitors, phosphatase inhibitors, ATPase inhibitors, tyrphostins,protease inhibitors, inhibitors herbimycin A, genistein, erbstatin, andlavendustin A. In some embodiments, additional therapeutic active agentsmay be selected from, but are not limited to, one or a combination ofthe following class of agents: alkylating agents, plant alkaloids, DNAtopoisomerase inhibitors, anti-folates, pyrimidine analogs, purineanalogs, DNA antimetabolites, taxanes, podophyllotoxins, hormonaltherapies, retinoids, photosensitizers or photodynamic therapies,angiogenesis inhibitors, antimitotic agents, isoprenylation inhibitors,cell cycle inhibitors, actinomycin, bleomycin, anthracyclines, MDRinhibitors and Ca²⁺ ATPase inhibitors. The term “radiotherapeutic agent”as used herein, is intended to refer to any radiotherapeutic agent knownto one of skill in the art to be effective to treat or amelioratecancer, without limitation. For instance, the radiotherapeutic agent canbe an agent such as those administered in brachytherapy or radionuclidetherapy. Such methods can optionally further comprise the administrationof one or more additional cancer therapies, such as, but not limited to,chemotherapies, and/or another radiotherapy.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for reducing CD95-mediated lymphocyte(e.g. T cell) motility. In some embodiments, the polypeptide or fusionprotein of the present invention is particularly suitable for thetreatment of an auto-immune disease. As used herein, an “autoimmunedisease” is a disease or disorder arising from and directed at anindividual's own tissues. Examples of autoimmune diseases include, butare not limited to Addison's Disease, Allergy, Alopecia Areata,Alzheimer's disease, Antineutrophil cytoplasmic antibodies(ANCA)-associated vasculitis, Ankylosing Spondylitis, Antiphospho lipidSyndrome (Hughes Syndrome), arthritis, Asthma, Atherosclerosis,Atherosclerotic plaque, autoimmune disease (e.g., lupus, RA, MS, Graves'disease, etc.), Autoimmune Hemolytic Anemia, Autoimmune Hepatitis,Autoimmune inner ear disease, Autoimmune Lymphoproliferative syndrome,Autoimmune Myocarditis, Autoimmune Oophoritis, Autoimmune Orchitis,Azoospermia, Behcet's Disease, Berger's Disease, Bullous Pemphigoid,Cardiomyopathy, Cardiovascular disease, Celiac Sprue/Coeliac disease,Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), Chronic idiopathicpolyneuritis, Chronic Inflammatory Demyelinating, Polyradicalneuropathy(CIPD), Chronic relapsing polyneuropathy (Guillain-Barr syndrome),Churg-Strauss Syndrome (CSS), Cicatricial Pemphigoid, Cold AgglutininDisease (CAD), chronic obstructive pulmonary disease (COPD), CRESTsyndrome, Crohn's disease, Dermatitis, Herpetiformus, Dermatomyositis,diabetes, Discoid Lupus, Eczema, Epidermolysis bullosa acquisita,Essential Mixed Cryoglobulinemia, Evan's Syndrome, Exopthalmos,Fibromyalgia, Goodpasture's Syndrome, Hashimoto's Thyroiditis,Idiopathic Pulmonary Fibrosis, Idiopathic Thrombocytopenia Purpura(ITP), IgA Nephropathy, immunoproliferative disease or disorder (e.g.,psoriasis), Inflammatory bowel disease (IBD), including Crohn's diseaseand ulcerative colitis, Insulin Dependent Diabetes Mellitus (IDDM),Interstitial lung disease, juvenile diabetes, Juvenile Arthritis,juvenile idiopathic arthritis (JIA), Kawasaki's Disease, Lambert-EatonMyasthenic Syndrome, Lichen Planus, lupus, Lupus Nephritis, LymphoscyticLypophisitis, Meniere's Disease, Miller Fish Syndrome/acute disseminatedencephalomyeloradiculopathy, Mixed Connective Tissue Disease, MultipleSclerosis (MS), muscular rheumatism, Myalgic encephalomyelitis (ME),Myasthenia Gravis, Ocular Inflammation, Pemphigus Foliaceus, PemphigusVulgaris, Pernicious Anaemia, Polyarteritis Nodosa, Polychondritis,Polyglandular Syndromes (Whitaker's syndrome), Polymyalgia Rheumatica,Polymyositis, Primary Agammaglobulinemia, Primary BiliaryCirrhosis/Autoimmune cholangiopathy, Psoriasis, Psoriatic arthritis,Raynaud's Phenomenon, Reiter's Syndrome/Reactive arthritis, Restenosis,Rheumatic Fever, rheumatic disease, Rheumatoid Arthritis, Sarcoidosis,Schmidt's syndrome, Scleroderma, Sjörgen's Syndrome, Stiff-Man Syndrome,Systemic Lupus Erythematosus (SLE), systemic scleroderma, TakayasuArteritis, Temporal Arteritis/Giant Cell Arteritis, Thyroiditis, Type 1diabetes, Type 2 diabetes, Ulcerative colitis, Uveitis, Vasculitis,Vitiligo, and Wegener's Granulomatosis.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for the treatment of systemic lupuserythematosus.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for the treatment of an inflammatorycondition. The term “inflammatory condition” as used herein refers toacute or chronic localized or systemic responses to harmful stimuli,such as pathogens, damaged cells, physical injury or irritants, that aremediated in part by the activity of cytokines, chemokines, orinflammatory cells (e.g., neutrophils, monocytes, lymphocytes,macrophages) and is characterized in most instances by pain, redness,swelling, and impairment of tissue function. The inflammatory conditionmay be selected from the group consisting of: sepsis, septicemia,pneumonia, septic shock, systemic inflammatory response syndrome (SIRS),Acute Respiratory Distress Syndrome (ARDS), acute lung injury,aspiration pneumanitis, infection, pancreatitis, bacteremia,peritonitis, abdominal abscess, inflammation due to trauma, inflammationdue to surgery, chronic inflammatory disease, ischemia,ischemia-reperfusion injury of an organ or tissue, tissue damage due todisease, tissue damage due to chemotherapy or radiotherapy, andreactions to ingested, inhaled, infused, injected, or deliveredsubstances, glomerulonephritis, bowel infection, opportunisticinfections, and for subjects undergoing major surgery or dialysis,subjects who are immunocompromised, subjects on immunosuppressiveagents, subjects with HIV/AIDS, subjects with suspected endocarditis,subjects with fever, subjects with fever of unknown origin, subjectswith cystic fibrosis, subjects with diabetes mellitus, subjects withchronic renal failure, subjects with bronchiectasis, subjects withchronic obstructive lung disease, chronic bronchitis, emphysema, orasthma, subjects with febrile neutropenia, subjects with meningitis,subjects with septic arthritis, subjects with urinary tract infection,subjects with necrotizing fasciitis, subjects with other suspected GroupA streptococcus infection, subjects who have had a splenectomy, subjectswith recurrent or suspected enterococcus infection, other medical andsurgical conditions associated with increased risk of infection, Grampositive sepsis, Gram negative sepsis, culture negative sepsis, fungalsepsis, meningococcemia, post-pump syndrome, cardiac stun syndrome,stroke, congestive heart failure, hepatitis, epiglotittis, E. coli0157:H7, malaria, gas gangrene, toxic shock syndrome, pre-eclampsia,eclampsia, HELP syndrome, mycobacterial tuberculosis, Pneumocysticcarinii, pneumonia, Leishmaniasis, hemolytic uremic syndrome/thromboticthrombocytopenic purpura, Dengue hemorrhagic fever, pelvic inflammatorydisease, Legionella, Lyme disease, Influenza A, Epstein-Barr virus,encephalitis, inflammatory diseases and autoimmunity includingRheumatoid arthritis, osteoarthritis, progressive systemic sclerosis,systemic lupus erythematosus, inflammatory bowel disease, idiopathicpulmonary fibrosis, sarcoidosis, hypersensitivity pneumonitis, systemicvasculitis, Wegener's granulomatosis, transplants including heart,liver, lung kidney bone marrow, graft-versus-host disease, transplantrejection, sickle cell anemia, nephrotic syndrome, toxicity of agentssuch as OKT3, cytokine therapy, and cirrhosis.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for preventing Th17 celltransmigration. Accordingly, the polypeptide or fusion protein of thepresent invention is particularly suitable for treating Th17 mediateddiseases. The term “Th17-mediated disease” is used herein in thebroadest sense and includes all diseases and pathological conditions thepathogenesis of which involves abnormalities of Th17 cells. As usedherein, the term “Th17 cells” has its general meaning in the art andrefers to a subset of T helper cells producing interleukin 17 (IL-17).“A brief history of T(H)17, the first major revision in the T(H)1/T(H)2hypothesis of T cell-mediated tissue damage”. Nat. Med. 13 (2):139-145.). The term “IL-17” has its general meaning in the art andrefers to the interleukin-17A protein. Typically, Th17 cells arecharacterized by classical expression of Th cell markers at their cellsurface such as CD4, and by the expression of IL17. Typically, asreferenced herein, a Th17 cell is a IL-17+ cell. Examples of Th17mediated diseases include but are not limited to autoimmune diseases,inflammatory diseases, osteoclasia, and transplantation rejection ofcells, tissue and organs. In particular, the above-mentionedTh17-mediated diseases may be one or more selected from the groupconsisting of Behcet's disease, polymyositis/dermatomyositis, autoimmunecytopenias, autoimmune myocarditis, primary liver cirrhosis,Goodpasture's syndrome, autoimmune meningitis, Sjögren's syndrome,systemic lupus erythematosus, Addison's disease, alopecia greata,ankylosing spondylitis, autoimmune hepatitis, autoimmune mumps, Crohn'sdisease, insulin-dependent diabetes mellitus, dystrophic epidermolysisbullosa, epididymitis, glomerulonephritis, Graves' disease,Guillain-Barré syndrome, Hashimoto's disease, hemolytic anemia, multiplesclerosis, myasthenia gravis, pemphigus vulgaris, psoriasis, rheumaticfever, rheumatoid arthritis, sarcoidosis, scleroma, spondyloarthropathy,thyroiditis, vasculitis, vitiligo, myxedema, pernicious anemia andulcerative colitis.

Typically, the polypeptide or fusion protein of the present invention isadministered to the subject in a therapeutically effective amount. By a“therapeutically effective amount” is meant a sufficient amount of thepolypeptide or fusion protein of the present invention for reaching atherapeutic effect (e.g. treating cancer). It will be understood,however, that the total daily usage of the compounds and compositions ofthe present invention will be decided by the attending physician withinthe scope of sound medical judgment. The specific therapeuticallyeffective dose level for any particular subject will depend upon avariety of factors including the disorder being treated and the severityof the disorder; activity of the specific compound employed; thespecific composition employed, the age, body weight, general health, sexand diet of the subject; the time of administration, route ofadministration, and rate of excretion of the specific compound employed;the duration of the treatment; drugs used in combination orcoincidential with the specific polypeptide employed; and like factorswell known in the medical arts. For example, it is well within the skillof the art to start doses of the compound at levels lower than thoserequired to achieve the desired therapeutic effect and to graduallyincrease the dosage until the desired effect is achieved. However, thedaily dosage of the products may be varied over a wide range from 0.01to 1,000 mg per adult per day. Typically, the compositions contain 0.01,0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 250 and 500mg of the active ingredient for the symptomatic adjustment of the dosageto the subject to be treated. A medicament typically contains from about0.01 mg to about 500 mg of the active ingredient, typically from 1 mg toabout 100 mg of the active ingredient. An effective amount of the drugis ordinarily supplied at a dosage level from 0.0002 mg/kg to about 20mg/kg of body weight per day, especially from about 0.001 mg/kg to 7mg/kg of body weight per day.

In some embodiments, the therapeutic method of the present comprises thesteps of i) determining the level of i) determining the level of solubleCD95L in a blood sample obtained from the subject ii) comparing thelevel determined at step i) with a predetermined reference value andiii) administering the subject with a therapeutically effective amountof the polypeptide or fusion protein of the present invention when thelevel determined at step i) is higher than the predetermined referencevalue.

As used herein the term CD95L has its general meaning in the art antrefers to the cognate ligand of CD95 that is a transmembrane protein. Asused herein the term “soluble CD95L” has its general meaning in the artand refers to the soluble ligand produced by the cleavage of thetransmembrane CD95L (also known as FasL) (Matsuno et al., 2001;Vargo-Gogola et al., 2002; Kiaei et al., 2007; Kirkin et al., 2007; orSchulte et al., 2007). The term “serum CD95L”, “soluble CD95L”,“metalloprotease-cleaved CD95L” and “cl-CD95L” have the same meaningalong the specification.

According to the invention, the measure of the level of soluble CD95Lcan be performed by a variety of techniques. Typically, the methods maycomprise contacting the sample with a binding partner capable ofselectively interacting with soluble CD95L in the sample. In someaspects, the binding partners are antibodies, such as, for example,monoclonal antibodies or even aptamers. The aforementioned assaysgenerally involve the binding of the partner (i.e. antibody or aptamer)to a solid support. Solid supports, which can be used in the practice ofthe present invention include substrates such as nitrocellulose (e.g.,in membrane or microtiter well form); polyvinylchloride (e.g., sheets ormicrotiter wells); polystyrene latex (e.g., beads or microtiter plates);polyvinylidine fluoride; diazotized paper; nylon membranes; activatedbeads, magnetically responsive beads, and the like. The level of solubleCD95L may be measured by using standard immunodiagnostic techniques,including immunoassays such as competition, direct reaction, or sandwichtype assays. Such assays include, but are not limited to, agglutinationtests; enzyme-labelled and mediated immunoassays, such as ELISAs;biotin/avidin type assays; radioimmunoassays; immunoelectrophoresis;immunoprecipitation. An exemplary biochemical test for identifyingspecific proteins employs a standardized test format, such as ELISAtest, although the information provided herein may apply to thedevelopment of other biochemical or diagnostic tests and is not limitedto the development of an ELISA test (see, e.g., Molecular Immunology: ATextbook, edited by Atassi et al. Marcel Dekker Inc., New York and Basel1984, for a description of ELISA tests). It is understood thatcommercial assay enzyme-linked immunosorbant assay (ELISA) kits forvarious plasma constituents are available. Therefore ELISA method can beused, wherein the wells of a microtiter plate are coated with a set ofantibodies, which recognize soluble CD95L. A sample containing orsuspected of containing soluble CD95L is then added to the coated wells.After a period of incubation sufficient to allow the formation ofantibody-antigen complexes, the plate(s) can be washed to remove unboundmoieties and a detectably labelled secondary binding molecule added. Thesecondary binding molecule is allowed to react with any captured samplemarker protein, the plate washed and the presence of the secondarybinding molecule detected using methods well known in the art.Typically, levels of immunoreactive soluble CD95L in a sample may bemeasured by an immunometric assay on the basis of a double-antibody“sandwich” technique, with a monoclonal antibody specific for solubleCD95L (Cayman Chemical Company, Ann Arbor, Mich.). According to saidembodiment, said means for measuring soluble CD95L level are for examplei) a soluble CD95L buffer, ii) a monoclonal antibody that interactsspecifically with soluble CD95L, iii) an enzyme-conjugated antibodyspecific for soluble CD95L and a predetermined reference value ofsoluble CD95L.

Another object of the present invention relates to a pharmaceuticalcomposition comprising a polypeptide or the fusion protein or thenucleic acid sequence or the expression vector or the host cellaccording to the invention and a pharmaceutically acceptable carrier.Typically, the polypeptide or the fusion protein or the nucleic acidsequence or the expression vector or the host cell according to theinvention may be combined with pharmaceutically acceptable excipients,and optionally sustained-release matrices, such as biodegradablepolymers, to form therapeutic compositions. “Pharmaceutically” or“pharmaceutically acceptable” refer to molecular entities andcompositions that do not produce an adverse, allergic or other untowardreaction when administered to a mammal, especially a human, asappropriate. A pharmaceutically acceptable carrier or excipient refersto a non-toxic solid, semi-solid or liquid filler, diluent,encapsulating material or formulation auxiliary of any type.

In the pharmaceutical compositions of the present invention for oral,sublingual, subcutaneous, intramuscular, intravenous, transdermal, localor rectal administration, the active principle, alone or in combinationwith another active principle, can be administered in a unitadministration form, as a mixture with conventional pharmaceuticalsupports, to animals and human beings. Suitable unit administrationforms comprise oral-route forms such as tablets, gel capsules, powders,granules and oral suspensions or solutions, sublingual and buccaladministration forms, aerosols, implants, subcutaneous, transdermal,topical, intraperitoneal, intramuscular, intravenous, subdermal,transdermal, intrathecal and intranasal administration forms and rectaladministration forms.

Typically, the pharmaceutical compositions contain vehicles, which arepharmaceutically acceptable for a formulation capable of being injected.These may be in particular isotonic, sterile, saline solutions(monosodium or disodium phosphate, sodium, potassium, calcium ormagnesium chloride and the like or mixtures of such salts), or dry,especially freeze-dried compositions which upon addition, depending onthe case, of sterilized water or physiological saline, permit theconstitution of injectable solutions. The pharmaceutical forms suitablefor injectable use include sterile aqueous solutions or dispersions;formulations including sesame oil, peanut oil or aqueous propyleneglycol; and sterile powders for the extemporaneous preparation ofsterile injectable solutions or dispersions. In all cases, the form mustbe sterile and must be fluid to the extent that easy syringabilityexists. It must be stable under the conditions of manufacture andstorage and must be preserved against the contaminating action ofmicroorganisms, such as bacteria and fungi. Solutions comprisingcompounds of the present invention as free base or pharmacologicallyacceptable salts can be prepared in water suitably mixed with asurfactant, such as hydroxypropylcellulose. Dispersions can also beprepared in glycerol, liquid polyethylene glycols, and mixtures thereofand in oils. Under ordinary conditions of storage and use, thesepreparations contain a preservative to prevent the growth ofmicroorganisms. The polypeptide or fusion protein of the presentinvention can be formulated into a composition in a neutral or saltform. Pharmaceutically acceptable salts include the acid addition salts(formed with the free amino groups of the protein) and which are formedwith inorganic acids such as, for example, hydrochloric or phosphoricacids, or such organic acids as acetic, oxalic, tartaric, mandelic, andthe like. Salts formed with the free carboxyl groups can also be derivedfrom inorganic bases such as, for example, sodium, potassium, ammonium,calcium, or ferric hydroxides, and such organic bases as isopropylamine,trimethylamine, histidine, procaine and the like. The carrier can alsobe a solvent or dispersion medium containing, for example, water,ethanol, polyol (for example, glycerol, propylene glycol, and liquidpolyethylene glycol, and the like), suitable mixtures thereof, andvegetables oils. The proper fluidity can be maintained, for example, bythe use of a coating, such as lecithin, by the maintenance of therequired particle size in the case of dispersion and by the use ofsurfactants. The prevention of the action of microorganisms can bebrought about by various antibacterial and antifungal agents, forexample, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, andthe like. In many cases, it will be preferable to include isotonicagents, for example, sugars or sodium chloride. Prolonged absorption ofthe injectable compositions can be brought about by the use in thecompositions of agents delaying absorption, for example, aluminiummonostearate and gelatin. Sterile injectable solutions are prepared byincorporating the active compounds in the required amount in theappropriate solvent with several of the other ingredients enumeratedabove, as required, followed by filtered sterilization. Generally,dispersions are prepared by incorporating the various sterilized activeingredients into a sterile vehicle which contains the basic dispersionmedium and the required other ingredients from those enumerated above.In the case of sterile powders for the preparation of sterile injectablesolutions, the preferred methods of preparation are vacuum-drying andfreeze-drying techniques which yield a powder of the active ingredientplus any additional desired ingredient from a previouslysterile-filtered solution thereof. The preparation of more, or highlyconcentrated solutions for direct injection is also contemplated, wherethe use of DMSO as solvent is envisioned to result in extremely rapidpenetration, delivering high concentrations of the active agents to asmall tumor area. Upon formulation, solutions will be administered in amanner compatible with the dosage formulation and in such amount as istherapeutically effective. The formulations are easily administered in avariety of dosage forms, such as the type of injectable solutionsdescribed above, but drug release capsules and the like can also beemployed. For parenteral administration in an aqueous solution, forexample, the solution should be suitably buffered if necessary and theliquid diluent first rendered isotonic with sufficient saline orglucose. These particular aqueous solutions are especially suitable forintravenous, intramuscular, subcutaneous and intraperitonealadministration. In this connection, sterile aqueous media which can beemployed will be known to those of skill in the art in light of thepresent disclosure. Some variation in dosage will necessarily occurdepending on the condition of the subject being treated. The personresponsible for administration will, in any event, determine theappropriate dose for the individual subject.

In some embodiments, the polypeptide or fusion protein of the presentinvention is particularly suitable for use in screening methods foridentifying drugs for reducing CD95-mediated cell motility in a subject.

Accordingly a further aspect of the present invention consists of amethod for screening a drug for reducing CD95-mediated cell motilitycomprising the steps consisting of a) determining the ability of acandidate compound to inhibit the interaction between CD95 and apolypeptide or fusion protein of the present invention and b) positivelyselecting the candidate compound that inhibits said interaction.

At step a), any method suitable for the screening of protein-proteininteractions is suitable. Whatever the embodiment of step a) of thescreening method, the complete CD95 protein and polypeptide or fusionprotein of the present invention may be used as the binding partners.Alternatively, fragments of CD95 protein that include the site ofinteraction are used. Therefore in some embodiments, the step a) of thescreening method of the present invention consists of determining theability of the candidate compound to inhibit the binding between twopolypeptides or fusion protein of the present invention.

In some embodiments, step a) consists in generating physical valueswhich illustrate or not the ability of the candidate compound to inhibitthe interaction between the two polypeptides or fusion proteins of thepresent invention and comparing said values with standard physicalvalues obtained in the same assay performed in the absence of the saidcandidate compound. The “physical values” that are referred to above maybe of various kinds depending of the binding assay that is performed,but notably encompass light absorbance values, radioactive signals andintensity value of fluorescence signal. If after the comparison of thephysical values with the standard physical values, it is determined thatthe said candidate compound modulates the binding between said firstpolypeptide and said second polypeptide, then the candidate ispositively selected at step b).

In some embodiments, the polypeptide or fusion protein of the presentinvention is labeled with a detectable molecule for the screeningpurposes. Typically, the detectable molecule may consist of any compoundor substance that is detectable by spectroscopic, photochemical,biochemical, immunochemical or chemical means. For example, usefuldetectable molecules include radioactive substance (including thosecomprising 32P, 25S, 3H, or 125I), fluorescent dyes (including5-bromodesosyrudin, fluorescein, acetylaminofluorene or digoxigenin),fluorescent proteins (including GFPs and YFPs), or detectable proteinsor peptides (including biotin, polyhistidine tails or other antigen tagslike the HA antigen, the FLAG antigen, the c-myc antigen and the DNPantigen). In some embodiments, the detectable molecule is located at, orbound to, an amino acid residue located outside the said amino acidsequence of interest, in order to minimise or prevent any artefact forthe binding between said polypeptides or between the candidate compoundand or any of the polypeptides.

In some embodiments, the polypeptides of the present invention are fusedwith a GST tag (Glutathione S-transferase). In this embodiment, the GSTmoiety of the said fusion protein may be used as detectable molecule. Inthe said fusion protein, the GST may be located either at the N-terminalend or at the C-terminal end. The GST detectable molecule may bedetected when it is subsequently brought into contact with an anti-GSTantibody, including with a labelled anti-GST antibody. Anti-GSTantibodies labelled with various detectable molecules are easilycommercially available.

In some embodiments, the polypeptides of the present invention are fusedwith a poly-histidine tag. Said poly-histidine tag usually comprises atleast four consecutive histidine residues and generally at least sixconsecutive histidine residues. Such a polypeptide tag may also compriseup to 20 consecutive histidine residues. Said poly-histidine tag may belocated either at the N-terminal end or at the C-terminal end. In thisembodiment, the poly-histidine tag may be detected when it issubsequently brought into contact with an anti-poly-histidine antibody,including with a labelled anti-poly-histidine antibody.Anti-poly-histidine antibodies labelled with various detectablemolecules are easily commercially available.

In some embodiments, the polypeptides of the present invention are fusedwith a protein moiety consisting of either the DNA binding domain or theactivator domain of a transcription factor. Said protein moiety domainof transcription may be located either at the N-terminal end or at theC-terminal end. Such a DNA binding domain may consist of the well-knownDNA binding domain of LexA protein originating form E. Coli. Moreoversaid activator domain of a transcription factor may consist of theactivator domain of the well-known Gal4 protein originating from yeast.

In some embodiments of the screening method according to the invention,polypeptides or fusion proteins of the present comprise a portion of atranscription factor. In said assay, the binding together of the firstand second portions generates a functional transcription factor thatbinds to a specific regulatory DNA sequence, which in turn inducesexpression of a reporter DNA sequence, said expression being furtherdetected and/or measured. A positive detection of the expression of saidreporter DNA sequence means that an active transcription factor isformed, due to the binding together of said polypeptides or fusionproteins of the present invention. Usually, in a two-hybrid assay, thefirst and second portion of a transcription factor consist respectivelyof (i) the DNA binding domain of a transcription factor and (ii) theactivator domain of a transcription factor. In some embodiments, the DNAbinding domain and the activator domain both originate from the samenaturally occurring transcription factor. In some embodiments, the DNAbinding domain and the activator domain originate from distinctnaturally occurring factors, while, when bound together, these twoportions form an active transcription factor. The term “portion” whenused herein for transcription factor, encompass complete proteinsinvolved in multi protein transcription factors, as well as specificfunctional protein domains of a complete transcription factor protein.Therefore in some embodiments of the present invention, step a) of thescreening method of the present invention comprises the following steps:(1) providing a host cell expressing:

-   -   a first fusion protein between (i) a polypeptide of the present        invention and (ii) a first protein portion of transcription        factor    -   a second fusion protein between (i) a polypeptide of the present        invention and (ii) a second portion of a transcription factor

said transcription factor being active on DNA target regulatory sequencewhen the first and second protein portion are bound together and

said host cell also containing a nucleic acid comprising (i) aregulatory DNA sequence that may be activated by said activetranscription factor and (ii) a DNA report sequence that is operativelylinked to said regulatory sequence

(2) bringing said host cell provided at step 1) into contact with acandidate compound to be tested

(3) determining the expression level of said DNA reporter sequence

The expression level of said DNA reporter sequence that is determined atstep (3) above is compared with the expression of said DNA reportersequence when step (2) is omitted. A different expression level of saidDNA reporter sequence in the presence of the candidate compound meansthat the said candidate compound effectively inhibits the bindingbetween the two polypeptides of the present invention and that saidcandidate compound may be positively selected a step b) of the screeningmethod.

Suitable host cells include, without limitation, prokaryotic cells (suchas bacteria) and eukaryotic cells (such as yeast cells, mammalian cells,insect cells, plant cells, etc.). However preferred host cell are yeastcells and more preferably a Saccharomyces cerevisiae cell or aSchizosaccharomyces pombe cell. Similar systems of two-hybrid assays arewell know in the art and therefore can be used to perform the screeningmethod according to the invention (see. Fields et al. 1989; Vasavada etal. 1991; Fearon et al. 1992; Dang et al., 1991, Chien et al. 1991, U.S.Pat. No. 5,283,173, U.S. Pat. No. 5,667,973, U.S. Pat. No. 5,468,614,U.S. Pat. No. 5,525,490 and U.S. Pat. No. 5,637,463). For instance, asdescribed in these documents, the Gal4 activator domain can be used forperforming the screening method according to the invention. Gal4consists of two physically discrete modular domains, one acting as theDNA binding domain, the other one functioning as thetranscription-activation domain. The yeast expression system describedin the foregoing documents takes advantage of this property. Theexpression of a Gal1-LacZ reporter gene under the control of aGal4-activated promoter depends on the reconstitution of Gal4 activityvia protein-protein interaction. Colonies containing interactingpolypeptides are detected with a chromogenic substrate forβ-galactosidase. A compete kit (MATCHMAKER, TM) for identifyingprotein-protein interactions is commercially available from Clontech. Insome embodiments, a first polypeptide of the present invention is fusedto the DNA binding domain of Gal4 and a second polypeptide of thepresent invention as above defined is fused to the activation domain ofGal4. The expression of said detectable marker gene may be assessed byquantifying the amount of the corresponding specific mRNA produced.However, usually the detectable marker gene sequence encodes fordetectable protein, so that the expression level of the said detectablemarker gene is assessed by quantifying the amount of the correspondingprotein produced. Techniques for quantifying the amount of mRNA orprotein are well known in the art. For example, the detectable markergene placed under the control of regulatory sequence may consist of theβ-galactosidase as above described.

In some embodiments, the first polypeptides or fusion proteins of thepresent invention are labelled with a fluorescent molecule or substrate.Therefore, the potential alteration effect of the candidate compound tobe tested on the binding between the 2 polypeptides or fusion proteinsof the present invention is determined by fluorescence quantification.

In some embodiments, the detectable molecule is a protein fragmentcomplementation system, wherein one protein fragment fused to onepolypeptide of the present invention is complementary to another proteinfragment fused to the other polypeptide of the present invention andcomplementation of protein fragments generates a measurable signal(protein fragment complementation assay). In some embodiments, thecomplementary protein fragments generate an active enzyme. In someembodiments, the active enzyme is β-lactamase that can generate acolored product from a substrate such as nitrocefin, a fluorescentproduct from the substrate such as Fluorocillin Green, or abioluminescent product (in combination with firefly luciferase) from asubstrate such as Bluco (β-lactam-D-luciferin). In some embodiments, theactive enzyme is a luciferase that can generate bioluminescence from asubstrate such as D-luciferin for firefly luciferase and coelenterazineluciferin for renilla and gaussia luciferases.

In some embodiments, the polypeptides of the present invention arelabelled with fluorescent molecules that are suitable for performingfluorescence detection and/or quantification for the binding betweensaid polypeptides using fluorescence energy transfer (FRET) assay orBRET (bioluminescence resonance energy transfer).

In some embodiments, the donor detectable molecule is a bioluminescentenzyme that can transfer resonance energy (BRET). For example, aluciferase enzyme typically generates light upon oxidation of itssubstrate, but can also transfer the energy to a fluorophore that is inproximity. In some embodiments, the bioluminescent enzyme is expressedas a fusion protein with a first polypeptide of the present invention.In some embodiments, the bioluminescent protein is firefly, renilla, orgaussia luciferase. In some embodiments, the acceptor fluorophore is afluorescent protein that is fused to a second polypeptide of the presentinvention. In some embodiments, the acceptor fluorophore is an organicor inorganic.

In some embodiments, a first polypeptide of the present invention islabelled with a first fluorophore substance and a second polypeptide ofthe present invention is labelled with a second fluorophore substance.The first fluorophore substance may have a wavelength value that issubstantially equal to the excitation wavelength value of the secondfluorophore, whereby the bind of said first and second polypeptides isdetected by measuring the fluorescence signal intensity emitted at theemission wavelength of the second fluorophore substance. Alternatively,the second fluorophore substance may also have an emission wavelengthvalue of the first fluorophore, whereby the binding of said and secondpolypeptides is detected by measuring the fluorescence signal intensityemitted at the wavelength of the first fluorophore substance. Thefluorophores used may be of various suitable kinds, such as thewell-known lanthanide chelates. These chelates have been described ashaving chemical stability, long-lived fluorescence (greater than 0.1 mslifetime) after bioconjugation and significant energy-transfer inspecificity bio affinity assay. Document U.S. Pat. No. 5,162,508discloses bipyridine cryptates. Polycarboxylate chelators with TEKEStype photosensitizers (EP0203047A1) and terpyridine typephotosensitizers (EP0649020A1) are known. Document WO96/00901 disclosesdiethylenetriaminepentaacetic acid (DPTA) chelates which usedcarbostyril as sensitizer. Additional DPT chelates with other sensitizerand other tracer metal are known for diagnostic or imaging uses (e.g.,EP0450742A1).

In some embodiments, the fluorescence assay performed at step a) of thescreening method consists of a Homogeneous Time Resolved Fluorescence(HTRF) assay, such as described in document WO 00/01663 or U.S. Pat. No.6,740,756, the entire content of both documents being hereinincorporated by reference. HTRF is a TR-FRET based technology that usesthe principles of both TRF (time-resolved fluorescence) and FRET. Morespecifically, the one skilled in the art may use a HTRF assay based onthe time-resolved amplified cryptate emission (TRACE) technology asdescribed in Leblanc et al. (2002). The HTRF donor fluorophore isEuropium Cryptate, which has the long-lived emissions of lanthanidescoupled with the stability of cryptate encapsulation. XL665, a modifiedallophycocyanin purified from red algae, is the HTRF primary acceptorfluorophore. When these two fluorophores are brought together by abiomolecular interaction, a portion of the energy captured by theCryptate during excitation is released through fluorescence emission at620 nm, while the remaining energy is transferred to XL665. This energyis then released by XL665 as specific fluorescence at 665 nm. Light at665 nm is emitted only through FRET with Europium. Because EuropiumCryptate is always present in the assay, light at 620 nm is detectedeven when the biomolecular interaction does not bring XL665 within closeproximity.

Therefore in some embodiments, step a) of the screening method maytherefore comprises the steps consisting of:

(1) bringing into contact a pre-assay sample comprising:

-   -   a first polypeptide of the present invention fused to a first        antigen,    -   a second polypeptide of the present invention fused to a second        antigen    -   a candidate compound to be tested

(2) adding to the said pre assay sample of step (2):

-   -   at least one antibody labelled with a European Cryptate which is        specifically directed against the first said antigen    -   at least one antibody labelled with XL665 directed against the        second said antigen

(3) illuminating the assay sample of step (2) at the excitationwavelength of the said European Cryptate

(4) detecting and/or quantifying the fluorescence signal emitted at theXL665 emission wavelength

(5) comparing the fluorescence signal obtained at step (4) to thefluorescence obtained wherein pre assay sample of step (1) is preparedin the absence of the candidate compound to be tested.

If at step (5) as above described, the intensity value of thefluorescence signal is different (lower or higher) than the intensityvalue of the fluorescence signal found when pre assay sample of step (1)is prepared in the absence of the candidate compound to be tested, thenthe candidate compound may be positively selected at step b) of thescreening method. Antibodies labelled with a European Cryptate orlabelled with XL665 can be directed against different antigens ofinterest including GST, poly-histidine tail, DNP, c-myx, HA antigen andFLAG which include. Such antibodies encompass those which arecommercially available from CisBio (Bedford, Mass., USA), and notablythose referred to as 61GSTKLA or 61HISKLB respectively.

The candidate compounds that have been positively selected at the end ofany one of the embodiments of the in vitro screening which has beendescribed previously in the present specification may be subjected tofurther selection steps in view of further assaying its properties onthe CD95-mediated cell motility (e.g, CD95-mediated Ca2+ response orcell migration). For this purpose, the candidate compounds that havebeen positively selected with the general in vitro screening method asabove described may be further selected for their to reduce or inhibitCD95-mediated Ca2+ response and/or cell migration induced by solubleCD95L. Thus, in some embodiments, the screening method of the presentinvention comprises the steps of: i) screening for candidate compoundsthat inhibit the interaction between CD95 and the polypeptide or fusionprotein of the present invention, by performing the in vitro screeningmethod as above described and ii) screening the candidate compoundspositively selected at the end of step i) for their ability to reduceCD95-mediated Ca2+ response and/or CD95-mediated cell motility (e.g.cell migration mediated by soluble CD95L). In some embodiments, the stepii) of said screening method comprises the following steps: (1) bringinginto contact a cell with a candidate compound that has been positivelyselected at the end of step i), (2) determining the capacity of compoundto inhibit or reduce CD95-mediated Ca2+ response and/or cell migrationinduced by soluble CD95L and (3) comparing the CD95-mediated Ca2+response and/or cell migration determined at step (2) with theCD95-mediated Ca2+ response and/or cell migration determined when step(1) is performed in the absence of the said positively selectedcandidate compound, and (4) positively selecting the candidate compoundwhen the CD95-mediated Ca2+ response and/or cell migration determined atstep (2) is lower than the CD95-mediated Ca2+ response and/or cellmigration determined when step (1) is performed in the absence of thesaid candidate compound. In some embodiments, the cell is selected fromthe group consisting of T cell and cancer cells (e.g. breast cancercells such as TNBC cells (MDA-MB-231)). Typically a migration assay or aCD95-mediated Ca2+ response assay as described in the EXAMPLE may beused. Step (1) as above described may be performed by adding an amountof the candidate compound to be tested to the culture medium. Usually, aplurality of culture samples are prepared, so as to add increasingamounts of the candidate compound to be tested in distinct culturesamples. Generally, at least one culture sample without candidatecompound is also prepared as a negative control for further comparison.Optionally, at least one culture sample with an already known agent thatreduces the CD95-mediated Ca2+ response and/or cell migration is alsoprepared as a positive control for standardization of the method.Therefore, step (3) may be performed by comparing the percentage ofcells wherein the CD95-mediated Ca2+ response and/or cell migration ismodulated obtained for the cell cultures incubated with the candidatecompound to be tested with the percentage of cells wherein theCD95-mediated Ca2+ response and/or cell migration is modulated obtainedfor the negative control cell cultures without the candidate compound.Illustratively, the efficiency of the candidate compound may be assessedby comparing (i) the percentage of cells wherein the CD95-mediated Ca2+response and/or cell migration is reduced with (ii) the percentage ofcells wherein the CD95-mediated Ca2+ response and/or cell migration isreduced measured in the supernatant of the cell cultures that wereincubated with the known agent that modulates the CD95-mediated Ca2+response and/or cell migration. Further illustratively, the efficiencyof the candidate compound may be assessed by determining for whichamount of the candidate compound added to the cell cultures thepercentage of cells wherein the CD95-mediated Ca2+ response and/or cellmigration is reduced is close or higher than the percentage of cellswherein the CD95-mediated Ca2+ response and/or cell migration is reducedwith the known agent that inhibits or reduces the CD95-mediated Ca2+response and/or cell migration.

In some embodiments, the candidate compound of may be selected from thegroup consisting of peptides, peptidomimetics, small organic molecules,or nucleic acids. For example the candidate compound according to theinvention may be selected from a library of compounds previouslysynthetized, or a library of compounds for which the structure isdetermined in a database, or from a library of compounds that have beensynthetized de novo. In a particular embodiment, the candidate compoundmay be selected form small organic molecules. As used herein, the term“small organic molecule” refers to a molecule of size comparable tothose organic molecules generally sued in pharmaceuticals. The termexcludes biological macromolecules (e.g.; proteins, nucleic acids,etc.); preferred small organic molecules range in size up to 2000 Da,and most preferably up to about 1000 Da.

The invention will be further illustrated by the following figures andexamples. However, these examples and figures should not be interpretedin any way as limiting the scope of the present invention.

FIGURES

FIG. 1: Cleaved-CD95L mobilizes Calcium ions from both extracellular andintracellular compartments by mechanisms involving Ca²⁺ channels, PLCγ,IP3 and Ryanodine Receptors. [Ca²⁺], was monitored via the ratio F340nm/F380 nm (relative [Ca²⁺]cytosolic) using Fura2 as fluorescent probe.Data represent mean+/−SD of at least 60 cells (3 independentexperiments). Jurkat cells were stimulated with 100 ng/ml cl-CD95L(black arrow). A. Cells were bathed in a 2 mM Ca²⁺-containing medium(black squares) or in a Ca²⁺-free medium (open circles). The transientCa²⁺ increase occurring in Ca²⁺-free medium (open circles) correspondsto the release of calcium ions stored in intracellular compartments. Theplateau phase observed in 2 mM Ca²⁺-containing medium, and disappearingin Ca²⁺-free medium is mainly due to calcium influx from theextracellular space. B. In PLCγ1−/− Jurkat cells (open circles),cl-CD95L failed to induce the initial, transient increase in [Ca²⁺]i,which is restored when PLCγ1 is reintroduced in the PLCγ1−/− cells(black squares). C. Jurkat cells were pretreated (2 μM, 20 minutes) withXestospongin C (XestoC, open circles), a membrane permeable, potent IP3receptors blocker. Such a treatment again, completely blocked theinitial component of the calcium response. D. Jurkat cells werepretreated (20 minutes) with high concentrations (10 μM) of Ryanodine(Rya, open triangle), in order to block Ryanodine receptors, or withRyanodine and Xestospongin C (XestoC, open circle) to block bothryanodine and IP3 receptors. Rya did not reduce the initial peak butblocked the plateau phase. Combination of Rya and XestoC abolished theCD95-mediated Ca²⁺ response.

FIG. 2: TAT CID 175-210 and TAT CID 175-191 impair thePLCγ/IP3-dependent calcium response to cl-CD95L. [Ca²⁺] was monitoredvia the ratio F340 nm/F380 nm (relative [Ca²⁺]cytosolic) using Fura2 asfluorescent probe. Data represent mean+/−SD of at least 60 cells (3independent experiments). Jurkat (A and B) and activated PBL (C and D)were stimulated with 100 ng/ml Cl-CD95L (black arrow). A. Jurkat werepre-incubated with a TAT peptide control (1 hr, 10 μM, open triangle) orwith a TAT peptide corresponding to the aa 192-210 of the death receptorCD95 (1 hr, 10 μM, open circles) or not (control, black squares). Thetreatments did not significantly modify the calcium response tocl-CD95L. B. Jurkat were pre-incubated with a TAT peptide correspondingto the aa 175-210 of the death receptor CD95 (1 hr, 10 μM, open circles)or with a TAT peptide corresponding to the aa 175-191 of the deathreceptor CD95 (1 hr, 10 μM, open triangles) or not (black squares). Bothtreatments greatly reduced the calcium response to cl-CD95L,particularly the initial peak. C. Activated PBL were pre-incubated withthe TAT peptide control (1 hr, 10 μM, open triangles) or with the TATpeptide corresponding to the aa 192-210 of the death receptor CD95 (1hr, 10 μM, open circles) or not (control, black squares). The treatmentsdid not significantly modify the calcium response to Cl-CD95L. D.Activated PBL were pre-incubated with a TAT peptide corresponding to theaa 175-210 of the death receptor CD95 (1 hr, 10 μM, open circles) orwith a TAT peptide corresponding to the aa 175-191 of the death receptorCD95 (1 hr, 10 μM, open triangles) or not (black squares). Bothtreatments greatly reduced the calcium response to cl-CD95L,particularly the initial peak.

FIG. 3: TAT CID 175-210 is effective in various cell models. [Ca²⁺] wasmonitored via the ratio F340 nm/F380 nm (relative [Ca²⁺]cytosolic) usingFura2 as fluorescent probe. Data represent mean+/−SD of at least 60cells (3 independent experiments). CEM (A), MDA MB 231(B) and MEF (C)were stimulated with 100 ng/ml cl-CD95L (black arrow). A and B. CEM andMDA MB 231 cells were pre-incubated with a TAT peptide corresponding tothe aa 175-210 of the death receptor CD95 (1 hr, 10 μM, open circle).The treatment (open circles) completely abolished the calcium responsein both cell types. C. MEFs were pre-incubated with the TAT peptidecorresponding to the aa 175-210 of the death receptor CD95 (1 hr, 10 μM,open circle) or with the TAT peptide control (1 hr, 10 μM, opentriangles). If the latter did not modify the initial phase, the formerblocked it.

FIG. 4: TAT CID 175-219 inhibits migration of triple cell negativecancer cells. The triple negative breast cancer cell line MDA-MB-231 waspre-incubated for 1 hour with 10 μM of DID 175-220 and cell migrationwas assessed using the Boyden chamber assay in the presence or absenceof cl-CD95L (100 ng/mL) for 24 h. Migrating cells were stained withGiemsa. For each experiment, five images of random fields were acquired.

FIG. 5. High amounts of serum CD95L in SLE patients correspond to ahomotrimeric ligand inducing endothelial transmigration of activated Tlymphocytes. A. Soluble CD95L was dosed by ELISA in sera of newlydiagnosed SLE patients and healthy donors. *** indicates P<0.0001 usinga two-tailed student's t test. B. Sera from SLE patient werefractionated using size exclusion S-300-HR Sephacryl columns and CD95Lwas dosed by ELISA. Inset: CD95L was immunoprecipitated in fractions40-46 and 76-78 and loaded in a 12% SDS-PAGE. Anti-CD95L immunoblot isdepicted. C. Activated PBLs from healthy donors were incubated inpresence of gel filtration fractions obtained in B and endothelialtransmigration was assessed as described in Materials and Methods. Whereindicated, fractions 76-78 were pre-incubated 30 minutes with theantagonist anti-CD95L mAb NOK-1 (10 μg/ml). D. CD95L, IL17 and CD4expression levels were analyzed by Immunohistochemistry in inflamedskins of lupus patients or in healthy subjects (mammectomy). Numberscorrespond to different patients. E. Densitometric analyses of CD95L andIL17 staining depicted in D revealed that the expression levels of thesetwo markers vary in a correlated manner. F. The indicated human T-cellsubsets were subject to transmigration assay in presence of sera takenfrom SLE patients or healthy donor as controls. Data were analyzed usingMann-Whitney U-test. ***P<0.001 G. Human T-cell subsets were subject totransmigration assay as above except in the lower chamber Fas-Fc wasadded at increasing concentrations in parallel with cl-CD95L. Datarepresent the mean of 4-5 individual donors±SD and were analyzed using a2-way Anova. H. Transmigration of CD4 T-cell subsets was analyzed inBoyden chambers in presence or absence of cl-CD95L (200 ng/ml). I.Transmigration of human regulatory T-cells and Th17 cells was assessedby Boyden Chamber assay in presence or absence of cl-CD95L. Data wasanalyzed using a 2-way Anova. P values<0.05 was considered significant;*P<0.05, ***P<0.001

FIG. 6. In vivo administration of cl-CD95L preferentially attracts Th17cells. Mice were injected once with cl-CD95L (200 ng) or vehicle, and 24hrs later subject to examination. (A-B). Total cell counts for theperitoneal cavity (A) and spleen (B) were performed. (C-D). Differentialwhite blood cell count was performed 24 hrs post injection. PeritonealExudate Cells (PEC) (C) and spleen (D) cells were subject to flowcytometry analysis to identify the percentage of infiltrated CD4⁺ cells.(E-I). PEC CD4⁺ cells were purified by AutoMACS separation and RNAprepared. Cells were subject to real-time PCR for (E) IL-17A, (F)IL-23R, (G) CCR6, (H) IFN-γ, and (I) FoxP3. Data presented are averagesof groups of 6 mice±SD, with experiments repeated twice. Data wereanalyzed using the students t-Test, P values <0.05 was consideredsignificant; *P<0.05, **P<0.01, ***P<0.001.

FIG. 7. CD95 implements a Death Domain-independent Ca²⁺ response. A. CEMcells were stimulated with CD95L (100 ng/mL) and CD95 wasimmunoprecipitated. The immune complex was resolved by SDS/PAGE, and theindicated immunoblottings were performed. Total lysates were loaded ascontrol. B. Parental Jurkat T cells, PLC-γ1-deficient and itsPLC-γ1-reconstituted counterparts were loaded with the Ca²⁺ probeFuraPE3-AM (1 μM) and then stimulated with cl-CD95L (100 ng/mL, blackarrow). Ratio images (F340/F380, R) were taken every 10 s and werenormalized vs pre-stimulated values (R₀). Data represent mean±SD of R/R₀measured in n cells. Inset: PLCγ1-deficient Jurkat cells or itsreconstituted counterpart was lysed and the expression levels of PLCγ1and CD95 were evaluated by immunoblotting. Tubulin was used as a loadingcontrol. C. Cells were loaded with the Ca²⁺ probe FuraPE3-AM (1 μM) andthen stimulated with cl-CD95L (100 ng/ml). Data were analyzed asdescribed in B. Inset: Parental Jurkat cells (A3) or its counterpartslacking either FADD or caspase-8 were lysed and the expression levels ofCD95, FADD and Caspase-8 were evaluated by immunoblotting. D.Representation of the different CD95 constructions. E. CEM-IRC cellsexpressing GFP alone or GFP-fused CD95 constructs shown in D, wereloaded with the Ca²⁺ probe fluo2-AM (1□M). The cells were thenstimulated with cl-CD95L (100 ng/mL; black arrow) and [Ca²⁺]_(i) wasmonitored via the ratio F/F₀ (relative Ca²⁺ _([CYT])). Data representmean±SD of F/F₀ measured in n cells

FIG. 8. The CD95-mediated Ca²⁺ signal stems from amino-acid residues 175to 210 in CD95. A. HEK cells were co-transfected with the GFP-fused CD95constructions and wild type PLCγ1. Twenty-four hours after transfection,CD95 expression level in these cells was evaluated by flow cytometry. B.Cells in A were stimulated with CD95L (100 ng/mL) and CD95 wasimmunoprecipitated. The immune complex was resolved by SDS-PAGE, and theindicated immunoblotting was performed. Total lysates were loaded as acontrol. C. Left Panel: HEK cells were co-transfected with PLCγ1 andCID-mCherry or mCherry alone. After 24 h, cells were lyzed and PLCγ1 wasimmunoprecipitated. The immune complex was resolved by SDS/PAGE, and theindicated immunoblottings were performed. Total lysates were loaded as acontrol. Right Panel: HEK cells were co-transfected with PLCγ1 andCID-mCherry or mCherry alone. After 24 h, cells were stimulated inpresence or absence of CD95L (100 ng/mL) and CD95 wasimmunoprecipitated. The immune complex was resolved by SDS-PAGE, and theindicated immunoblotting was performed. Total lysates were loaded as acontrol. D. Upper panel; protein sequences of TAT-CID and TAT-control.Lower panel; The leukemic T cell line CEM was pre-incubated for 1 h with10 μM of TAT-control or TAT-CID and then stimulated in presence orabsence of cl-CD95L (100 ng/mL) for the indicated times. Cells werelysed and CD95 was immunoprecipitated. The immune complex was resolvedby SDS-PAGE, and the indicated immunoblotting was performed. Totallysates were loaded as a control. E. Jurkat and CEM were loaded withFuraPE3-AM (1 μM), pretreated for 1 h with 10 μM of TAT-control orTAT-CID and then stimulated with 100 ng/ml of cl-CD95L (black arrow).Ratio images were taken every 10 s and were normalized vs pre-stimulatedvalues. F. Human PBLs from healthy donors were loaded with furaPE3-AM (1μM) pretreated for 1 h with 10 μM of TAT-control or TAT-CID or with theIP3R inhibitor Xestospongin C (positive control, 1 μM, 1 h) and thenstimulated with 100 ng/ml of cl-CD95L (black arrow). Ratio values (R)were normalized vs pre-stimulated values (R0). Data represent mean±SD ofR/R₀ measured in n cells.

FIG. 9. TAT-CID is an inhibitor of the cl-CD95L-induced Th17 cellaccumulation in organs. A. Mouse Th17 cell transmigration was monitoredby Boyden Chamber assay in presence or absence of the indicatedconcentrations of the TAT-CID peptide. B-D. C57BL/6 mice were injectedwith 40 mg/kg of TAT-control or TAT-CID two hours prior to IP injectioncl-CD95L (200 ng) or vehicle, and 24 hours later subject to examination.B. Total cell counts for the peritoneal cavity was performed. C.Peritoneal Exudate Cells (PEC) were subject to flow cytometry analysisto identify the percentage of infiltrated CD4⁺CD62L⁻ T-cells. D. IL-17Alevels in the peritoneal cavity were quantified by ELISA. Statisticalanalysis was performed using a 2-way Anova p-values indicated are**p<0.01, ***p<0.001.

EXAMPLE 1

Cells were loaded with Fura2-AM (1 μM) at resting temperature for 30 minin Hank's Balanced Salt Solution (HBSS). After washing with HBSS, thecells were incubated for 15 min in the absence of Fura2-AM to completede-esterification of the dye. Cells were placed in a thermostatedchamber (37° C.) of an inverted epifluorescence microscope (OlympusIX70) equipped with a ×40, UApo/340-1.15 W water-immersion objective(Olympus), and fluorescence micrograph images were captured at 510 nmand at 12-bit resolution by a fast-scan camera (CoolSNAP fx Monochrome,Photometrics). To minimize UV light exposure, 4×4 binning function wasused. Fura2-AM was alternately excited at 340 and 380 nm, and ratios ofthe resulting images (excitations at 340 and 380 nm and emission filterat 520 nm) were produced at constant intervals (5 s or 10 s according tothe stimulus). Fura-2 ratio (F_(ratio) 340/380) images were displayedand the F_(ratio) values from the regions of interest (ROIs) drawn onindividual cells were monitored during the experiments and analyzedlater offline with Universal Imaging software, including Metafluor andMetamorph. Each experiment was independently repeated 3 times, and foreach experimental condition, we displayed an average of more than 20single-cell traces. Fluorescent images were pseudocolored using the IMDdisplay mode in MetaFluor and assembled without further manipulation inPhotoshop (Adobe). Raw data were acquired with MetaFluor and graphed inOrigin (OriginLab). [Ca²⁺]_(i) was calculated using the followingequation: [Ca²⁺]_(i)=K_(d)(R−R_(min))/(R−R_(max))×Sf2/Sf1, where K_(d)is the Fura2-AM dissociation constant at the two excitation wavelengths(F₃₄₀/F₃₈₀); R_(min) is the fluorescence ratio in the presence ofminimal calcium, obtained by chelating Ca²⁺ with 10 mM EGTA; R_(max) isthe fluorescence ratio in the presence of excess calcium, obtained bytreating cells with 1 μM ionomycin; Sf2 is the fluorescence of theCa²⁺-free form; and Sf1 is the fluorescence of the Ca²⁺-bound form ofFura2-AM at excitation wavelengths of 380 and 340 nm, respectively. Insome experiments cells were placed in a Ca²⁺-free medium consisting ofthe HBSS described above in which CaCl₂ was omitted and 100 μM EGTA wasadded in order to chelate residual Ca²⁺ ions. This medium was added tothe cells just before recording to avoid leak of the intracellularcalcium stores. Results are shown in FIGS. 1-3.

EXAMPLE 2

Boyden chambers contained membranes with a pore size of 8 μm (Millipore,Molsheim, France). After hydration of the membranes, breast cancer cells(10⁵ cells per chamber) were added to the top chamber in low serum(1%)-containing medium. The bottom chamber was filled with low serum(1%)-containing medium in the presence or absence of cl-CD95L (100ng/mL). Cells were cultured for 24 h at 37° C. To quantify migration,cells were mechanically removed from the top-side of the membrane usinga cotton-tipped swab, and migrating cells from the reverse side werefixed with methanol and stained with Giemsa. For each experiment, fiverepresentative pictures were taken for each insert, then cells werelyzed and absorbance at 560 nm correlated to the amount of Giemsa stainwas measured. Results are shown in FIG. 4.

EXAMPLE 3 Methods

Patients and Ethics Statement

SLE patients fulfilled four or more of the 1982 revised ACR criteria forthe disease. All clinical investigations were conducted according to theprinciples expressed in the Declaration of Helsinki. Blood was sampledfrom patients diagnosed with SLE after written consent was obtained fromeach individual. This study was approved by institutional review boardat the Centre Hospitalier Universitaire de Bordeaux.

Antibodies Other Reagents

PHA, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT),protease and phosphatase inhibitors were purchased from Sigma-Aldrich(L'Isle-d'Abeau-Chesnes, France). Anti-CD95L mAb was from Cell SignalingTechnology (Boston, Mass., USA). Recombinant IL-2 was obtained fromPeproTech Inc. (Rocky Hill, N.J., USA). Anti-PLCγ1 was purchased fromMillipore (St Quentin en Yvelines, France). Anti-CD95 mAbs (APO1-3) camefrom Enzo Life Sciences (Villeurbanne). PE-conjugated anti-human CD95(DX2) mAb, anti-human FADD mAb (clone1), neutralizing anti-CD95L mAb(Nok1) were provided by BD Biosciences (Le Pont de Claix, France).Anti-caspase-8 (C15) and anti-Fas (C-20) mAbs were from Santa CruzBiotechnology (Heidelberg, Germany). CD95-Fc, neutralizing anti-ICAM-1and E-selectin mAbs.

Plasmids and Constructs

GFP-tagged human CD95 (hCD95) constructs were obtained by PCR andinserted in frame between the Nhe1 and EcoR1 sites of pEGFP-N1(Clontech). Note that for all CD95 constructs the numbering takes intoconsideration the subtraction of 16 amino-acid of the signal peptide.Substitution of the cysteine at position 183 by a valine in hCD95⁽¹⁻²¹⁰⁾was performed using the Quickchange Lightning Site-directed Mutagenesiskit (Agilent Technologies, Les Ulis, France) according to manufacturerinstructions. The CID-mCHERRY construct was obtained by PCR amplifyingthe hCD95 sequence coding for the residues 175 to 210. The resultingfragment was inserted between the EcoR1 and BamH1 site of a pmCHERRY-N1vector. Mouse full length CD95 (mCD95) was kindly provided by Dr PascalSchneider (Universite de Lausanne, Lausanne, Switzerland). The mCD95sequence lacking the signal peptide (SP—residues 1-21) was amplified byPCR. After digestion by BamHI/EcoRI, the amplicon was inserted intopcDNA3.1(+) vector in frame with SP sequence of the influenza virushemagglutinin protein followed by a flag tag sequence and a 6 amino acidlinker. The pTriEx-4 vector encoding for Myc-tagged full-length humanPLCγ1 was a gift from Dr. Matilda Katan (Chester Beatty Laboratories,The Institute of Cancer Research, London, United Kingdom). Plasmidscoding for full length CD95L and the secreted IgCD95L have beendescribed elsewhere (Tauzin et al., 2011). All constructs were validatedby sequencing on both strands (GATC Biotech, Constance, Germany).

Cell Lines and Peripheral Blood Lymphocytes

All cells were purchased from ATCC (Molsheim Cedex, France). T leukemiccell lines CEM, H9 and Jurkat were cultured in RPMI supplemented with 8%heat-inactivated FCS (v/v) and 2 mM L-glutamine at 37° C. in a 5% CO2incubator. CEM-IRC cell expressing a low amount of plasma membrane CD95was described in (Beneteau et al., 2007; Beneteau et al., 2008). HEK293cells were cultured in DMEM supplemented with 8% heat-inactivated FCSand 2 mM L-glutamine at 37° C. in a 5% CO2 incubator. PBMCs (peripheralblood mononuclear cells) from healthy donors were isolated by Ficollcentrifugation, washed twice in PBS. Monocytes were removed by a 2 hoursadherence step and the naive PBLs (peripheral blood lymphocytes) wereincubated overnight in RPMI supplemented with 1 μg/ml of PHA. Cells werewashed extensively and incubated in the culture medium supplemented with100 units/ml of recombinant IL-2 for 5 days. Human umbilical veinendothelial cell (HUVEC) (Jaffe et al., 1973) were grown in humanendothelial serum free medium 200 supplemented with LSGS (Low serumgrowth supplement) (Invitrogen, Cergy Pontoise, France). CEM-IRC cellswere electroporated using BTM-830 electroporation generator (BTXInstrument Division, Harvard Apparatus) with 10 μg of DNA. 24 hoursafter electroporation, cells were treated for one week with 1 mg/mL ofneomycin and then clones were isolated using limiting dilution.

Immunohistocytology

Skins from lupus patients were embedded in paraffin and cut into 4 μmsections. For CD4, CD8 and IL17 detection, Immunohistochemical stainingwas performed on the Discovery Automated IHC stainer using the VentanaOmniMap detection kit (Ventana Medical Systems, Tucson, Ariz., USA). Theslides were rinsed with Ventana Tris-based Reaction buffer (Roche).Following deparaffination with Ventana EZ Prep solution (Roche) at 75°C. for 8 min, antigen retrieval was performed using Ventana proprietary,Tris-based buffer solution CC1 (pH8) antibody, at 95° C. to 100° C. for48 min. Endogen peroxidase was blocked with Inhibitor-D 3% H2O2(Ventana) for 10 min at 37° C. After rinsing, slides were incubated at37° C. for 60 min with IL17 (Bioss), CD4 and CD8 (Dako), and secondaryantibody: OmniMap HRP for 32 min (Roche). Signal enhancement wasperformed using the Ventana ChromoMap Kit Slides (biotin free detectionsystem). For CD95L (BD Pharmigen) detection, antigen retrieval wasperformed using antigen unmasking solution pH 9 (Vector) at 95° C. for40 min and endogenous peroxidase was blocked using 3% w/v hydrogenperoxide in methanol for 15 min. Slides were incubated in 5% BSA for 30min at RT and then stained overnight at 4° C. Tissue sections wereincubated with Envision+ system HRP-conjugated secondary antibodies for30 min at RT and labeling was visualized by adding liquid DAB+. Sectionswere counterstained (hematoxylin) and mounted with DPX mounting medium.Using ImageJ software (IHC toolbox), densitometry analysis wasundertaken on scanned slides to evaluate the amount of the differentmarkers. The mean area for each marker was assessed and we determined ifa correlation existed between the quantities of IL17-expressing cellsand CD8⁺ T cells and the expression level of CD95L.

Mouse and Human CD4⁺ T-Cell Subset Generation

Animal experiments were subject to ethical review by the University ofNottingham were appropriate and conducted using PPL 40/3412 inaccordance with the UK Home Office guidance and under ASPA (1986). Forthe generation of murine T-cell subsets, spleens were removed fromC57Bl/6 mice and single cell suspensions prepared. CD4⁺CD62L⁺ naívecells were isolated using Miltenyi Biotec microbeads. Nave human CD4⁺T-cells were prepared using the Miltenyi Biotec naïve CD4⁺ T-cellisolation kit II, which are sorted produced a 99% pure population ofCD4⁺CD45RA⁺ cells. Purified cells were cultured in complete IMDM mediaall with α-CD3 (1 μg/ml), α-CD28 (2 μg/ml), and as follows; Th1 cellsIL-12 (10 ng/ml) with α-IL-4 (10 μg/ml), Th2 cells IL-4 (10 ng/ml) andα-IFN-γ (10 μg/ml), Th17 cells Il-6 (10 ng/ml), TGF-β1 (2 ng/ml),α-IFN-γ (10 μg/ml) with α-IL-4 (10 μg/ml), and Tregs IL-2 (10 ng/ml)TGF-β1 (5 ng/ml), α-IFN-γ (10 μg/ml) and α-IL-4 (10 μg/ml). Cells wereconverted to T-cell subsets over five days as outlined above. Allcytokines were supplied by PeproTech (London, UK). Mouse CD3 (clone2C11); human CD3 (UCHT1); mouse CD28 (37.51); human CD28 (CD28.2); mouseIL-4 (11B11); human IL-4 (MP4-25D2); mouse IFN-γ (XMG1.2); human IFN-γB27 came from BD Pharmigen.

In Vivo Administration of Cl-CD95L

Female C57BL/6 mice (Harlan UK) aged between 8-10 weeks were placed ingroups of 6 and administered IP. Twenty-four hours following injection,mice were sacrificed and periteonial cavities were washed with 5 ml ofPBS/2% FCS, blood smears were prepared, and spleens were collected.Blood smears and cytospins of periteonal cells (PECs) were stained withGiemsa and differential counts performed. Single cell suspensions ofspleens and PECs were prepared, cell counts performed, CD4+CD62− T-cellswere isolated with Miltenyi microbeads and number of cells determined bytrypan blue exclusion. For experiments where animals received TAT-mCIDor control peptides, 800 μg (40 mg/kg) was injected IP 2 hrs prior toadministration of cl-CD95L. All mouse experiments were performed underethical approval from the University of Nottingham local animal ethicscommittee and adhering to UK Home Office guidelines under the ProjectLicense 40/3412.

Metalloprotease-Cleaved and Ig-Fused CD95L Production

Ig-CD95L was generated in the laboratory as described in (Tauzin et al.,2011). HEK 293 cells maintained in an 8% FCS-containing medium weretransfected using Calcium/Phosphate precipitation method with 3 μg ofempty plasmid or wild type CD95L-containing vector. 16 hours aftertransfection, medium was replaced by OPTI-MEM (Invitrogen) supplementedwith 2 mM L-glutamine and 5 days later, media containing cleaved CD95Land exosome-bound full length CD95L were harvested. Dead cells anddebris were eliminated through two steps of centrifugation (4500 rpm/15minutes) and then exosomes were eliminated by an ultracentrifugationstep (100000 g/2 hours).

Size Exclusion Chromatography

Sera from 4 different SLE patients (5.10⁷ cells) were filtrated using a0.2 μm filter and then 5 ml was resolved using a mid range fractionationS300-HR Sephacryl column (GE Healthcare) equilibrated with PBS (pH 7.4).Using an AKTAprime purifier apparatus (GE Healthcare), fractions wereharvested with a flow rate of 0.5 mL/min. Fifty fractions were harvestedand analyzed by ELISA to quantify CD95L.

CD95L ELISA

Anti-CD95L ELISA (Diaclone, Besançon, France) was performed toaccurately quantify the cleaved-CD95L present in sera following themanufacturer's recommendations.

Immunoprecipitation

T-cells (5×10⁷ cells per condition) were stimulated with Ig-CD95L orcl-CD95L (100 ng/mL) for indicated times at 37° C. Cells were lysed,incubated with APO1.3 (1 ug/mL) for 15 min at 4° C. and CD95 wasimmunoprecipitated using A/G protein-coupled magnetic beads (Ademtech,Pessac, France) for 1 h. After extensive washing, the immune complex wasresolved by SDS-PAGE and immunoblotting was performed with indicatedantibodies.

Immunoblot Analysis

Cells were lyzed for 30 minutes at 4° C. in lysis buffer (25 mM HEPES pH7.4, 1% v/v Triton X-100, 150 mM NaCl, 2 mM EGTA supplemented with a mixof protease inhibitors (Sigma-Aldrich)). Protein concentration wasdetermined by the bicinchoninic acid method (PIERCE, Rockford, Ill.,USA) according to the manufacturer's protocol. Proteins were separatedon a 12% SDS-PAGE and transferred to a nitrocellulose membrane (GEHealthcare, Buckinghamshire, England). The membrane was blocked 15minutes with TBST (50 mM Tris, 160 mM NaCl, 0.05% v/v Tween 20, pH 7.8)containing 5% w/v dried skimmed milk (TBSTM). Primary antibody wasincubated overnight at 4° C. in TBSTM. The membrane was intensivelywashed (TBST) and then the peroxydase-labeled anti-rabbit or anti-mouse(SouthernBiotech, Birmingham, Ala., US) was added for 45 minutes. Theproteins were visualized with the enhanced chemiluminescence substratekit (ECL, GE Healthcare).

Transendothelial Migration of Activated T Lymphocytes

After hydration of the Boyden chamber membranes containing 3 □m poresize membranes (Millipore, Molsheim, France), activated T-lymphocytes(10⁶) were added to the top chamber on a confluent monolayer of HUVEC ina low serum (1%)-containing medium. The bottom chamber was filled withlow serum (1%)-containing medium in presence or absence of 100 ng/ml ofcl-CD95L. In experiments using human sera, 500 μl of serum from eitherhealthy donors or SLE patients was added in the lower reservoir. Cellswere cultured for 24 h at 37° C. in a 5% CO2, humidified incubator.Transmigrated cells were counted in the lower reservoir by flowcytometry using a standard of 2.5×10⁴ fluorescent beads (Flow-count,Beckman Coulter).

Endothelial Cell Adhesion Assay

Blocking antibodies were used against E-selectin and ICAM-1 in theCHEMICON® endothelial cell adhesion assay (Millipore). Briefly, afteractivation of the endothelial cell layer with TNF-α, anti-mouse Igcontrols, anti-E-selectin or anti-ICAM-1 were added at finalconcentrations of 10 μg/ml. Thereafter calcein-AM-stained T-cell subsetswere incubated for 24 hours and unbound cells are washed. Cells attachedto the endothelium were assessed using fluorescence plate reader.

Real-Time qPCR

Single cell suspensions of spleens and PECs were prepared as describedabove. RNA was extracted from CD4 T-cells using phenol/chloroform. cDNAwas prepared using the Promega GO-Script Reverse Transcription Kit andused in Real-Time PCR. Briefly, cDNA samples were subject to Taqmanassay performed on a Roche Lightcycler. Results are reported asexpression levels were calculated using the Δct method relative to HPRT.

Video Imaging of the Calcium Response in Living Cells

Experiments on Parent Cell Lines

T cells were loaded with Fura-PE3-AM (1 μM) at room temperature for 30min in Hank's Balanced Salt Solution (HBSS). After washing, the cellswere incubated for 15 min in the absence of Fura-PE3-AM to completede-esterification of the dye. Cells were placed in the temperaturecontrolled chamber (37° C.) of an inverted epifluorescence microscope(Olympus IX70) equipped with an ×40 UApo/340-1.15 W water-immersionobjective (Olympus), and fluorescence micrograph images were captured at510 nm and 12-bit resolution by a fast-scan camera (CoolSNAP fxMonochrome, Photometrics). To minimize UV light exposure, a 4×4 binningfunction was used. Fura-PE3 was alternately excited at 340 and 380 nm,and the ratios of the resulting images (emission filter at 520 nm) wereproduced at constant intervals (10 seconds). The Fura-PE3 ratio(F_(ratio) 340/380) images were analyzed offline with Universal Imagingsoftware, including Metafluor and Metamorph. F_(ratio) reflects theintracellular Ca²⁺ concentration changes. Each experiment was repeated 3times, and the average of more than 20 single-cell traces was analyzed.

Experiments on GFP-Expressing Cell Lines

Fluo2-AM was used, instead of Fura-PE3-AM for experiments withGFP-expressing cells, because GFP fluorescence disturbs Ca²⁺ measurementwith Fura-PE3. As for Fura-PE3-AM, T cells were loaded with Fluo2-AM (1μM) for 30 min in Hank's Balanced Salt Solution (HBSS) and thenincubated for 15 min in the Fluo2-AM free HBSS to completede-esterification of the dye.Ca²⁺ changes were evaluated by excitingFluo2-AM-loaded cells at 535±35 nm. The values of the emittedfluorescence (605±50 nm) for each cell (F) were normalized to thestarting fluorescence (F₀) and reported as F/F₀ (relative Ca²⁺_([CYT])). Only GFP-positive cells were considered.

Results:

Serum CD95L in Lupus Patients Promotes Endothelial Transmigration ofActivated Th17 Cells

Recent reports suggest that a soluble form of CD95L increases inbronchoalveolar lavage fluid of patients suffering from acuterespiratory distress syndrome (ARDS). Surprisingly, this soluble CD95Lconserves its amino-terminal extracellular stalk region (amino acidresidues 103 to 136), a region normally eliminated after shedding bymetalloprotease of the membrane-bound CD95L (Herrero et al., 2011).Additionally under native conditions, this ARDS CD95L exhibited ahexameric stoichiometry and exerted a cytotoxic activity towardsalveolar epithelial cells in lungs (Herrero et al., 2011). These resultsencouraged us to evaluate the stoichiometry of serum CD95L in SLEpatients. First, we confirmed that soluble CD95L was significantlyincreased in the sera of 34 SLE patients as compared to 8 age-matchedhealthy donors (360±224.8 pg/ml in SLE patients vs 30.04±28.52 pg/ml inhealthy subjects, P<0.0001) (FIG. 5A). Second, these sera werefractionated using size-exclusion chromatography and CD95L concentrationwas quantified in each eluted fraction (FIG. 5B). CD95L was detected infractions 76 to 78, that contained proteins whose native molecular massranged between 75 and 80 kDa. This CD95L was next immunoprecipitated andresolved under denaturing/reducing conditions (SDS-PAGE) at 26 kDa (FIG.5B) indicating that the serum CD95L accumulated in lupus patientscorresponded to a homotrimeric ligand. Upon examination, we noted thatfunctionally this serum CD95L retained the previously reported activityof cleaved-CD95L (cl-CD95L), as it promoted the transmigration of Tlymphocytes across an endothelial monolayer (FIG. 5C). Specifically,significantly more activated T lymphocytes isolated from healthy donorsexposed to fractions 76-78 crossed endothelial monolayers in comparisonto lymphocytes exposed to fractions 42-44. These latter fractions, whichcontain exosome-bound CD95L (data not shown) failed to exert anypro-migratory effect (FIG. 5C). Furthermore, T-cell transmigrationinduced by fractions 76-78 was inhibited by up to 50% using aneutralizing anti-CD95L mAb (FIG. 5C) confirming that soluble CD95L inSLE patients plays a role in the endothelial transmigration of Tlymphocytes. If T-cell infiltration is involved in tissue damage andTh17 cells contribute to this clinical outcome through a CD95-drivenrecruitment, we assumed that CD95L-expressing cells should be detectedin the inflamed organs. Using immunohistochemistry, we evaluated thedistribution of CD95L and IL17-expressing cells in lupus patients withskin lesions. Of note, CD95L and IL17 staining were observed in skinbiopsies of lupus patients while they were undetectable in control skins(i.e., skins from breast reconstruction) (FIG. 5D). Moreover, CD95L wasmainly detected on endothelium of blood vessels, which were surroundedby immune cell infiltration (FIG. 5D). Moreover, a densitometricanalysis of lupus patients (n=10) highlighted that the amount of CD95Lwas correlated with the quantity of tissue-infiltrating IL17-expressingimmune cells suggesting that this ligand may represent a chemoattractantfor CD4⁺ Th17 cells (FIG. 5E). To further investigate if after cleavageby metalloprotease, CD95L exerted a chemoattractant activity toward allT-lymphocytes or selectively promoted migration of a sub-population,endothelial transmigration of naïve CD4⁺ T-cells isolated from healthydonors and subjected to in vitro differentiation was evaluated inpresence or absence of healthy or SLE sera. As compared to healthy sera,sera from SLE patients triggered a moderate increase in Th1transmigration while they dramatically enhanced endothelialtransmigration of Th17 cells (FIG. 5F). More importantly, thistransmigration process relied on CD95 signaling because pre-incubationof SLE sera with a decoy receptor (CD95-Fc) prevented Th17 cellmigration in a dose-dependent manner (FIG. 5G).

Both Th1 and Th17 T-cells have been reported to accumulate in enflamedorgans of lupus patients and lupus-prone mice contributing to diseasepathogenesis. To eliminate a putative role played by other serumcomponents in the observed phenomenon, we hereafter used a recombinantand homotrimeric version of CD95L. To this end, HEK 293 cells weretransfected with a full-length CD95L-encoding vector and we used themetalloprotease-cleaved CD95L (cl-CD95L) contained in this supernatant(Tauzin et al., 2011). Similarly to serum CD95L in lupus patients,cl-CD95L was more efficient to promote the transmigration of Th1 andTh17 lymphocytes as compared to undifferentiated Th0 and differentiatedTh2 cells (FIG. 5H). As imbalance of the Th17/T-regulatory (Treg) cellratio in enflamed organs has been suggested to participate in autoimmunedisorders and specifically lupus pathogenesis (Yang et al., 2009), wenext evaluated the effect of cl-CD95L on the transmigration of Tregcells. As shown in FIG. 5I, cl-CD95L enhanced endothelial transmigrationof Th17 T cells but failed to induce significant Treg transmigrationindicating that the accumulation of Th17 cells at the expense of Tregcells in the inflamed tissues of lupus patients. These findings revealedthat the higher levels of serum CD95L in SLE patients as compared tohealthy donors could contribute to the accumulation of Th17 cells ininflamed organs.

Cellular recruitment and trafficking can be controlled by expressionlevels of adhesion molecules on lymphocytes and their molecular partnerson endothelial cell surfaces. The expression of these molecules duringan inflammatory response is a dynamic process, which increases ordecreases the extravasation of immune cells into tissues. Recently, Th17cells have been shown to accumulate in organs as a result of theirinteraction with E-selectin during rolling and ICAM-1-dependent arreston activated endothelium (Alcaide et al., 2012). To address if thesemolecules contributed to the CD95-mediated endothelial T-cell migrationof Th17 cells, we evaluated the expression level of key adhesionmolecules on endothelial cells and differentiated Th cells in presenceor absence of cl-CD95L. Of note, while an important amount of E-selectinwas observed at the surface of HUVECs, no P-selectin was detected inthese cells. Moreover, cl-CD95L did not alter the expression level ofdifferent adhesion molecules on HUVEC. By contrast, in presence ofcl-CD95L, Th17 cells underwent up-regulation of P-selectin glycoprotein(PSGL-1), a ligand of E- and P-selectin, and ICAM-1 binding partnerLFA-1. The expression level of these ligands remained unaffected in Th1cells and tended towards a down-regulated state in Treg cells.Functionally the impact of PSGL-1 up-regulation in cl-CD95L-stimulatedTh17 cells was evaluated by use of an E-selectin neutralizing mAb.Anti-E-selectin inhibited more efficiently Th17 cell transmigration whencompared to similarly treated Th1 cells. Conversely blockade ofICAM-1/LFA-1 interactions by anti-ICAM-1 mAb impaired to a lesser extentboth Th1 and Th17 cell migration across endothelial cells. Thesefindings suggested that cl-CD95L promoted CD95-mediated Th17 celltransmigration by enhancing PSGL-1/E-selectin interaction.

Cl-CD95L Causes In Vivo a Rapid Accumulation of Th17 Cells.

To confirm in vivo the chemoattractant ability of cl-CD95L towards Th17cells, mice were injected intraperitoneally with a single dose ofcl-CD95L or vehicle and 24 hours later, composition of T-cellsinfiltrating the peritoneal cavity (peritoneal exudate cells—PECs) andthe spleen was examined. Total cell counts from the PEC and spleenrevealed a significant increase in the number of lymphocytes in thesecompartments as compared to vehicle-injected mice (FIG. 6A-B). Loss ofCD62L expression is associated with T-cell receptor engagement. Usingthis marker, we evaluated the amount of activated CD4⁺ T-cells(CD4⁺CD62L⁻) recruited into the spleen and the peritoneal cavity of miceinjected with or without cl-CD95L. We observed an increased amount of Tcells recruited in the peritoneal cavity and the spleen upon injectionof cl-CD95L as compared to control medium (FIG. 6C-D). Moreover, Q-PCRanalyses of key markers of the Th17 lineage including IL-17 (FIG. 6E),IL-23R (FIG. 6F), and CCR6 (FIG. 6G), performed on these activated CD4+T cells showed that cl-CD95L induced the recruitment of Th17 cells inthese tissues. Furthermore, there was no increase in levels of IFN-γ(Th1 cells) and FoxP3 (Treg) levels upon examination (FIG. 6H-I)strongly supporting that cl-CD95L acted primarily as a potentchemotactic ligand to Th17 T cells.

CD95 Triggers a Death Domain-Independent Ca′ Response

We recently showed that CD95 engagement evoked a Ca²⁺ response inactivated T lymphocytes that transiently inhibited the apoptotic signal(Khadra et al., 2011) and promoted cell motility (Tauzin et al., 2011).These observations raised the question of whether inhibition of thisCD95-mediated Ca²⁺ response can simultaneously inhibit cell migrationand enhance or at least unalter the apoptotic signal. T-cells exposed tocl-CD95L rapidly formed a molecular complex containing the phospholipaseCγ1 (PLCγ1) (FIG. 7A). Of note, the lack of this lipase in the T-cellline Jurkat caused a loss of the CD95-mediated Ca²⁺ signal, whilereconstitution of these cells with wild type PLCγ1 restored a calciumresponse similar to that of the parental T-cell line (FIG. 7B). Next, weinvestigated if the main components of the DISC were instrumental in theCD95-mediated calcium signal. To this end, the calcium signal wasassessed in FADD- and caspase-8-deficient Jurkat cells stimulated withcl-CD95L (FIG. 7C). Interestingly, although elimination of thesemolecules blocked the transmission of the apoptotic signaling pathway,it did not affect the CD95-mediated Ca²⁺ signal (FIG. 7C) indicatingthat PLCγ1 activation occurred independently of the DISC formation andthe implementation of cell death signal. These data prompted us toanalyze if the CD95-DD itself was necessary to trigger the Ca²⁺response. CD95 constructs devoid of either the entire intracellulardomain (CD95¹⁻¹⁷⁵), the DD (CD95¹⁻²¹⁰) or only the last 15 amino acidsinvolved in the FAP-1 recruitment (CD95¹⁻³⁰³) were generated (FIG. 7D).Protein-tyrosine phosphatase FAP-1 is reported to interact with thecarboxyl terminal 15 amino acids of CD95 (Sato et al., 1995) and preventits export from the cytoplasm to the cell surface (Ivanov et al., 2003).These constructs were expressed in a T-cell line selected for its lowexpression level of CD95 namely CEM-IRC ((Beneteau et al., 2008). WhileCEM-IRC cells showed a trivial sensitivity to cytotoxic CD95L,expression of CD95¹⁻³⁰³ or wild type CD95 in CEM-IRC cells to a levelsimilar to that of endogenous CD95 in parental CEM cells restored thetransmission of the apoptotic signaling pathway. By contrast, highlevels of CD95¹⁻¹⁷⁵ or CD95¹⁻²¹⁰ failed to induce cell death and aspreviously observed behave as dominant-negative receptors (Siegel etal., 2000). Also, reconstitution of CEM-IRC cells with wild type CD95and CD95¹⁻³⁰³ restored the CD95-mediated Ca²⁺ signal (FIG. 7E).Strikingly, while the loss of the death domain in the CD95¹⁻²¹⁰construct prevented the implementation of the apoptotic signal, it didnot affect the induction of the Ca²⁺ signal (FIG. 7E). Given that a CD95construct devoid of its whole intracellular region failed to evoke aCa⁺² response, we concluded that the Ca²⁺ response stems from the first36 amino acids in the CD95 intracellular region. To confirm that aminoacid residues 175 to 210 of CD95 were responsible for the Ca²⁺ response,we determined if this domain was capable to interact with PLCγ1. To thisend, GFP-fused CD95 constructs and wild type PLCγ1 were firsttransiently transfected in HEK cells, cells were stimulated with CD95L,lyzed and the immune complex associated with CD95 was analyzed byimmunoblotting. Although cells expressed similar levels of the differentCD95 chimeric constructs (FIG. 8A), the presence of PLCγ1 in the CD95immunoprecipitate was only lost with the CD95¹⁻¹⁷⁵ construct (FIG. 8B),while both CD95¹⁻²¹⁰ and CD95¹⁻¹⁷⁵ lost their capacity to recruit theadaptor protein FADD. Interestingly, a CD95 construct devoid of DDshowed a higher binding capacity for PLCγ1 as compared to wild type CD95(FIG. 8B) suggesting that this region may structurally or functionallyinterfere with the PLCγ1 binding to the 175-210 domain. Second, wegenerated a construct consisting of amino acids 175 to 210 that wedesignated calcium-inducing domain (CID) fused to mCherry. UnlikemCherry alone, CD95⁽¹⁷⁵⁻²¹⁰⁾-mCherry interacted with PLCγ1 and inhibitedits recruitment to CD95 (FIG. 8C) indicating that interference with thisjuxtamembrane domain may represent a way to prevent the CD95-mediatedCa²⁺ signal. Finally, to confirm this hypothesis, we synthesized a cellpenetrating peptide linking the 36-amino acid-stretch of CID to the9-amino acid HIV-TAT sequence (FIG. 8D), which serves as carrier totranslocate the whole protein across plasma membrane (Vives et al.,1997). Pre-incubation of the T cell lines Jurkat and CEM with theTAT-CID peptide impaired PLCγ1 recruitment (FIG. 8D) and abolished theinduction of the CD95-mediated Ca²⁺ signal (FIG. 8E). Similarly,pre-incubation of activated T lymphocytes from healthy subjects with theTAT-CID inhibited the PLCγ1 binding to CD95 (FIG. 54A) and abrogated theCD95-mediated Ca²⁺ response, in a similar way to xestospongin C, anantagonist of the calcium-releasing action ofinositol-1,4,5-trisphosphate (IP3), the substrate generated by PLCγ1activation (FIG. 8F). Moreover, TAT-CID pre-incubation inhibited Aktphosphorylation at its serine 473 (a hallmark of the PI3K signalingpathway activation) in PBLs exposed to cl-CD95L. Of note, althoughTAT-CID treatment inhibited the CD95-mediated Ca²⁺ and PI3K signals, itdid not affect the execution of the apoptotic signaling pathway. Inconclusion, we mapped a novel domain in CD95 designatedcalcium-initiating domain that recruited PLCγ1 and elicited the Ca²⁺response.

Because cysteine at position 183 is subject to palmitoylation promotingCD95 aggregation (Feig et al., 2007) and its redistribution into lipidraft (Chakrabandhu et al., 2007), we wondered whether this amino acidwas instrumental in the implementation of the CD95-mediated Ca²⁺ signal.To address this question and yet avoid any interference of the apoptoticsignaling in the CD95-mediated Ca²⁺ response, we reconstituted CEM-IRCcells with a CD95¹⁻²¹⁰ (no death domain) in which cysteine 183 wasreplaced by a valine. Both CD95¹⁻²¹⁰ and CD95^(1-210(C183V)) failed totrigger cell death in presence of Ig-CD95L, but they evoked a similarCa²⁺ response suggesting that the mechanism of palmitoylation was notinstrumental in inducing this cue. To confirm this observation, aTAT-CID peptide was synthesized in which cysteine was replaced by avaline. Pre-incubation of Jurkat cells and activated PBLs with thismutated peptide still inhibited the CD95-mediated Ca²⁺ responseconfirming that this cysteine did not contribute to the Ca²⁺ response incells exposed to cl-CD95L. Finally, we evaluated if the inhibitoryeffect of the TAT-CID was selective of the CD95-mediated Ca²⁺ signal. Ofnote, although TCR stimulation led to a PLCγ1-dependent Ca²⁺ response,TAT-CID pretreatment did not alter this signal. Similarly, thePLCβ-driven Ca²⁺ response evoked by carbachol, a cholinergic agonistknown to evoke a Ca²⁺ response through activation of G-protein-coupledreceptors, was not affected by TAT-CID treatment. These findingsindicated that the TAT-CID peptide exerted a selective inhibition of theCD95-mediated calcium signal.

Inhibition of the CD95-Mediated Ca²⁺ Signal Prevents Th17 CellTransmigration and Alleviates Clinical Signs in Lpr Mice.

To address if TAT-CID regimen may represent a therapeutic strategy inlupus, we first evaluated its effect in Th17 cell transmigration. Asshown in FIG. 9A, TAT-CID inhibited the CD95-mediated endothelialtransmigration of human Th17 cells in a dose-dependent manner. Alignmentof human and mouse CD95 proteins indicated a sequence divergence in theCID region suggesting that the human CID (TAT-hCID) may turn out to beinefficient to prevent the Ca²⁺ response induced in mouse T cells. Todetermine the inhibitory activity of TAT-hCID on the Ca²⁺ responseinduced by murin CD95, we first reconstituted CEM-IRC cells with wildtype mouse CD95. Both CD95-mediated apoptotic and Ca²⁺ signals wererestored in these cells as compared to parental CEM-IRC cells.Importantly, TAT-hCID failed to inhibit the CD95-mediated Ca²⁺ responsein mouse CD95-expressing CEM-IRC cells. By contrast, replacement of thehuman CID sequence by its mouse ortholog (TAT-mCID) abolished theCD95-mediated Ca²⁺ response in these cells. Similarly, TAT-mCID alsoinhibited the CD95-mediated Ca²⁺ signal in mouse T lymphocytesconfirming that despite the divergence between human and mouse CD95-CIDsequences (48.9% of sequence identity over the complete human and mouseCD95 sequences vs 21.2% over the two CIDs), these domains retained theproperty to trigger the Ca²⁺ signal in these species.

To further investigate the putative therapeutic activity of TAT-CID anddetermine whether this peptide exerted an inhibitory effect on Th17T-cell recruitment in vivo, we injected C57Bl/6 mice with 40 mg/kg ofTAT-control or TAT-CID two hours prior to the intraperitoneal injectionof cl-CD95L and the amount of T-cells infiltrating the peritoneal cavitywas evaluated 24 hours later. Total cell counts from the PEC revealedthat TAT-CID regimen abolished the CD95-mediated accumulation of Tlymphocytes in this compartment (FIG. 9B). In agreement with data shownin FIG. 2, cl-CD95L injection triggered an increased IL17 production inthe peritoneal cavity that was prevented by the TAT-CID treatment (FIG.9C). Furthermore, no differences were noted in levels of IFN-γ betweenmice injected with control peptide and TAT-CID peptide highlighting thatthe preferential recruitment of IL-17 secreting CD4 T-cells by cl-CD95Lwas abolished in vivo by administration of TAT-CID.

In conclusion, the selective inhibition of the CD95-mediated Ca²⁺ signalturned out to be a novel and promising therapeutic strategy to reduceTh17 cell accumulation in inflamed tissues of lupus patient withoutaltering the transmission of the apoptotic signal.

DISCUSSION

Our study provides new insights into the cellular and molecularmechanisms by which metalloprotease-cleaved CD95L enhances inflammationin SLE patients. We show that transmembrane CD95L is ectopicallyexpressed by endothelial cells covering blood vessels in the inflamedskins of lupus patients. More importantly, these CD95L⁺ vessels aresurrounded by a massive immune infiltrate strongly suggesting that thesestructures may serve as “open doors” for pro-inflammatory cells amongwhich Th17 cells. Exposed to cl-CD95L, these IL17-expressing cellsup-regulate PSGL-1 and LFA-1, two adhesion molecules involved in rollingand tethering of leukocytes to endothelial cells. Of note, T cells withthe highest levels of functional PSGL-1 also show the greatest capacityfor effector cytokine secretion and for cytotoxic activity (Baaten etal., 2013). Therefore, cl-CD95L may fuel the inflammatory process notonly by promoting the recruitment of activated Th1 and Th17 cells ininflamed tissues but also by altering the pattern of cytokine release inthese organs.

Recently, Coukos and colleagues demonstrated that CD95L is present inblood vessels of certain cancer tissues (i.e., ovary, colon, prostate,kidney) (Motz et al., 2014) and they associated this staining withscarce CD8⁺ infiltration. These authors showed that membrane-bound CD95Lon endothelial cells eliminated T cells and by doing so, preventedeffective anti-tumor immunity (Motz et al., 2014). We evaluated the CD8⁺T-cell infiltration around CD95L-positive blood vessels in lupuspatients and densitometric analysis revealed no inverted correlationbetween the amounts of CD95L and the quantity of infiltrating CD8⁺ Tcells. Given that CD95L exerts its chemottractant activity only afterits cleavage by metalloproteases (Tauzin et al., 2011), we assume thatat least in part, the discrepancy in the magnitude of immune infiltratessurrounding CD95⁺-blood vessels observed in certain cancers and lupuspatients may be caused by the absence or the presence, respectively of aCD95L-processing metalloprotease that remains to be identified.

Our study also uncovers the CD95 residues involved in the implementationof the Ca²⁺ signaling pathway. Even if our data show that CID interactswith PLCγ1 in unstimulated cells (FIG. 8C) suggesting that a directinteraction may occur between CD95 and this lipase, we can not rule outthat a third partner participates in this association. For example, arecent study showed that TRIP6 over-expressed in glioblastoma links theCID domain to the NF-kB signaling pathway and thereby promotesCD95-mediated cell migration in these cells (Lai et al., 2010).Nonetheless, the same authors did not detect TRIP6 in Jurkat T-cells andprecluded its participation in the non-apoptotic signal triggered in Tcells suggesting a tissue specific activity of this molecule (Lai etal., 2010). Within neuronal cells, the juxtamembrane domain of CD95(amino acid residues 175 to 188) interacts with ezrin an adaptormolecule linking CD95 to the actin network and thereby promotes neuriteoutgrowth via Rac1 activation and cytoskeletal remodeling (Desbarats etal., 2003). Cl-CD95L induces PLCγ1 recruitment rapidly (in the order ofthe minute) and transiently. Given that this signal stems from CID, thisjuxtamembrane domain of CD95 will require further analysis of itsstructure activity relationship to understand how it can evoke the Ca²⁺response without implementing the death domain-dependent andcaspase-driven apoptotic signaling pathway.

In this regard, the 175-210 amino acid residues of CD95 involved in theexecution of the Ca²⁺ response has never been crystallized probably dueto the fact that this region corresponds to an intrinsically disorderedregion (IDR) lacking a unique three dimensional structure. Usingdifferent molecular dynamic experiments, we confirmed that this peptidehas a very faint folding propensity. Computer simulation also showedthat the peptide shares another property of IDR: switches between orderand disorder states are frequent. Therefore, we surmise that the peptide(or a part of it) may stably fold in the presence of binding partners,starting from a pre-structured region such as helical segments observedby atomistic simulations (Sugase K. et al., Nature, 447, 1021-1025,2007; Wright & Dyson, Curr. Opin. Struct. Biol., 19, 31-38, 2009).Significantly, IDRs in proteins tend to take a central role in proteininteraction networks (Cumberworth et al., 2013). Indeed, thesedisordered regions can transiently interact with a large number ofpartners and thereby modulate cell signaling in a dynamic manner. Thismolecular feature is consistent with the participation of this domain ininducing a rapid and transient Ca²⁺ response promoting cell migration.

Also an analysis of mutations within CD95 found in different pathologiesrevealed that this region exhibits a lower amount of mutations ascompared to the adjacent death domain suggesting that in contrast to theDD, accumulation of mutations in this region may not confer a selectiveadvantage in carcinogenesis or contribute to the inflammatory process inALPS patients. Of note, before the etiology of ALPS type Ia wasassociated with mutations in CD95 gene, these patients were erroneouslydiagnosed as SLE patients.

A recent Phase I/II clinical trial found that a decoy receptor (known asAPG101) capable of blocking the CD95/CD95L interaction did not show anytoxicity in humans suffering from glioblastoma (Tuettenberg et al.,2012). We may envision that this therapeutic agent may, in a short-termperiod, benefit lupus patients. However, given that this inhibitor doesnot discriminate between the anti-tumor/infective functions of CD95L(i.e., the apoptotic signal) and its pro-inflammatory activity, it mayleads to deleterious side effects precluding its use in these SLEpatients. Because the apoptotic and the calcium signals stem from twoseparate and distant domains in CD95 and that inhibition of theCD95-mediated Ca²⁺ response does not prevent the apoptotic signalingpathway (Khadra et al., 2011), we propose that selective inhibition ofthe CD95-mediated Ca²⁺ response will provide an excellent opportunity toblock the pro-inflammatory activity of cl-CD95L in certain chronicinflammatory disorders without affecting the anti-tumor and infectiousroles of its membrane-bound counterpart.

REFERENCES

Throughout this application, various references describe the state ofthe art to which this invention pertains. The disclosures of thesereferences are hereby incorporated by reference into the presentdisclosure.

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1. A polypeptide having an amino acid sequence having at least 70%identity with an amino acid sequence ranging from an amino-acid residueat position 175 to an amino-acid residue at position 191, 192, 193, 194,195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208,209, or 210 in SEQ ID NO:1. 2-21. (canceled)
 22. The polypeptide ofclaim 1 which comprises 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29;30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47;48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65;66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83;84; 85; 86; 87; 88; 89; 90; 91; 92; 93; 94; 95; 96; 97; 98; 99; or 100amino acids.
 23. The polypeptide of claim 1 which comprises less than50, 30, 25 or 20 amino acids. 24-26. (canceled)
 27. A fusion proteincomprising a polypeptide having an amino acid sequence having at least70% identity with an amino acid sequence ranging from an amino-acidresidue at position 175 to an amino-acid residue at position 191, 192,193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206,207, 208, 209, or 210 in SEQ ID NO:1 fused directly or via a spacer toat least one heterologous polypeptide.
 28. The fusion protein of claim27 wherein the at least one heterologous polypeptide is acell-penetrating peptide, a Transactivator of Transcription (TAT) cellpenetrating sequence, a cell permeable peptide or a membranouspenetrating sequence.
 29. A nucleic acid sequence encoding a polypeptidehaving an amino acid sequence having at least 70% identity with an aminoacid sequence ranging from an amino-acid residue at position 175 to anamino-acid residue at position 191, 192, 193, 194, 195, 196, 197, 198,199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, or 210 in SEQ IDNO:1; or a fusion protein comprising the polypeptide.
 30. A vectorcomprising an expression cassette comprising a nucleic acid sequenceencoding i) a polypeptide having an amino acid sequence having at least70% identity with an amino acid sequence ranging from an amino-acidresidue at position 175 to an amino-acid residue at position 191, 192,193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206,207, 208, 209, or 210 in SEQ ID NO:1; or ii) a fusion protein comprisingthe polypeptide; wherein the nucleic acid sequence is associated withsuitable elements for controlling at least one of transcription andtranslation.
 31. A host cell comprising i) a nucleic acid sequenceencoding a polypeptide having an amino acid sequence having at least 70%identity with an amino acid sequence ranging from an amino-acid residueat position 175 to an amino-acid residue at position 191, 192, 193, 194,195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208,209, or 210 in SEQ ID NO:1; or a fusion protein comprising thepolypeptide; or ii) a vector comprising an expression cassettecomprising the nucleic acid sequence.
 32. The host cell of claim 31which is a prokaryotic or eukaryotic host cell.
 33. A method forproducing a polypeptide having an amino acid sequence having at least70% identity with an amino acid sequence ranging from an amino-acidresidue at position 175 to an amino-acid residue at position 191, 192,193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206,207, 208, 209, or 210 in SEQ ID NO:1, or a fusion protein comprising thepolypeptide, the method comprising the step of: (i) culturing atransformed host cell comprising a nucleic acid sequence encoding thepolypeptide or the fusion protein comprising the polypeptide, or avector comprising an expression cassette comprising the nucleic acidsequence, under conditions suitable to allow expression of saidpolypeptide or fusion protein; and (ii) recovering the expressedpolypeptide or fusion protein.
 34. A method of treating cancer, anauto-immune disease, an inflammatory condition or a Th17 mediateddisease condition in a subject in need thereof comprising administeringto the subject a therapeutically effective amount of i) a polypeptidehaving an amino acid sequence having at least 70% identity with an aminoacid sequence ranging from an amino-acid residue at position 175 to anamino-acid residue at position 191, 192, 193, 194, 195, 196, 197, 198,199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, or 210 in SEQ IDNO:1, or ii) a fusion protein comprising the polypeptide.
 35. The methodof claim 34 wherein the subject suffers from a triple negative breastcancer.
 36. (canceled)
 37. The method of claim 34, wherein the subjectsuffers from systemic lupus erythematosus. 38-39. (canceled)
 40. Amethod for screening a drug for reducing CD95-mediated cell motilitycomprising the steps of a) determining the ability of a candidatecompound to inhibit the interaction between CD95 and i) a polypeptidehaving an amino acid sequence having at least 70% identity with an aminoacid sequence ranging from an amino-acid residue at position 175 to anamino-acid residue at position 191 in SEQ ID NO:1, or ii) a fusionprotein comprising the polypeptide, and b) positively selecting thecandidate compound that inhibits said interaction.